diff --git a/backend/internal/ws/handler_test.go b/backend/internal/ws/handler_test.go
new file mode 100644
index 0000000..97cf697
--- /dev/null
+++ b/backend/internal/ws/handler_test.go
@@ -0,0 +1,563 @@
+package ws
+
+import (
+	"encoding/base64"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/gorilla/websocket"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"context"
+
+	"github.com/hhs/camtalk/internal/logger"
+	"github.com/hhs/camtalk/internal/models"
+	"github.com/hhs/camtalk/internal/orchestrator"
+	"github.com/hhs/camtalk/internal/session"
+)
+
+func init() {
+	logger.Init("debug", "console")
+	gin.SetMode(gin.TestMode)
+}
+
+// --- Mock Orchestrator ---
+
+// MockOrchestrator 实现 orchestrator.Orchestrator 接口，
+// 模拟完整的 STT → LLM → TTS 管道，通过 sender 推送消息。
+type MockOrchestrator struct {
+	// STTResult 模拟的语音识别结果
+	STTResult string
+	// LLMDeltas 模拟的 LLM 流式输出
+	LLMDeltas []string
+	// TTSAudios 模拟的 TTS 音频数据（每项一个 base64 编码的 MP3 片段）
+	TTSAudios []string
+	// Err 如果非 nil，ProcessQuery 直接返回此错误
+	Err error
+	// Delay 每个消息之间的延迟（用于 interrupt 测试）
+	Delay time.Duration
+}
+
+func (m *MockOrchestrator) ProcessQuery(
+	ctx context.Context,
+	sessionID string,
+	req models.WsQuery,
+	history []models.Message,
+	sender orchestrator.Sender,
+) error {
+	if m.Err != nil {
+		sender.SendError(models.WsError{
+			Type:      "error",
+			RequestID: req.RequestID,
+			Code:      "INTERNAL_ERROR",
+			Message:   m.Err.Error(),
+		})
+		return m.Err
+	}
+
+	// Step 1: 发送 STT 结果
+	if m.STTResult != "" {
+		_ = sender.SendSTTResult(models.WsSTTResult{
+			Type:      "stt_result",
+			RequestID: req.RequestID,
+			Text:      m.STTResult,
+			IsFinal:   true,
+		})
+	}
+	if m.Delay > 0 {
+		select {
+		case <-ctx.Done():
+			return nil // 中断视为正常完成
+		case <-time.After(m.Delay):
+		}
+	}
+
+	// Step 2: 发送 LLM chunks
+	var fullText strings.Builder
+	for _, delta := range m.LLMDeltas {
+		select {
+		case <-ctx.Done():
+			return nil // 中断视为正常完成
+		default:
+		}
+		fullText.WriteString(delta)
+		_ = sender.SendLLMChunk(models.WsLLMChunk{
+			Type:      "llm_chunk",
+			RequestID: req.RequestID,
+			Delta:     delta,
+			Role:      "assistant",
+		})
+		if m.Delay > 0 {
+			select {
+			case <-ctx.Done():
+				return nil // 中断视为正常完成
+			case <-time.After(m.Delay):
+			}
+		}
+	}
+
+	// Step 3: 发送 TTS 音频
+	for i, audio := range m.TTSAudios {
+		select {
+		case <-ctx.Done():
+			return nil // 中断视为正常完成
+		default:
+		}
+		isLast := i == len(m.TTSAudios)-1
+		_ = sender.SendTTSAudio(models.WsTTSAudio{
+			Type:      "tts_audio",
+			RequestID: req.RequestID,
+			Audio:     audio,
+			MimeType:  "audio/mp3",
+			IsLast:    isLast,
+		})
+	}
+
+	// Step 4: 发送 llm_done
+	_ = sender.SendLLMDone(models.WsLLMDone{
+		Type:      "llm_done",
+		RequestID: req.RequestID,
+		FullText:  fullText.String(),
+		Model:     "gpt-4o",
+		LatencyMs: 100,
+	})
+
+	return nil
+}
+
+// --- 测试辅助函数 ---
+
+// setupTestServer 创建测试用 Gin 服务器和 WebSocket URL。
+func setupTestServer(t *testing.T, orch orchestrator.Orchestrator) (*httptest.Server, string) {
+	t.Helper()
+
+	sessionMgr := session.NewMemoryManager(5*time.Minute, 20)
+	t.Cleanup(func() { sessionMgr.Stop() })
+
+	r := gin.New()
+	r.GET("/ws", ServeWS(sessionMgr, orch))
+
+	srv := httptest.NewServer(r)
+
+	// 构造 WebSocket URL
+	wsURL := "ws" + strings.TrimPrefix(srv.URL, "http") + "/ws"
+
+	return srv, wsURL
+}
+
+// connectWS 建立 WebSocket 连接并返回 conn。
+func connectWS(t *testing.T, wsURL string) *websocket.Conn {
+	t.Helper()
+
+	conn, _, err := websocket.DefaultDialer.Dial(wsURL, nil)
+	require.NoError(t, err, "WebSocket 连接失败")
+	t.Cleanup(func() { conn.Close() })
+	return conn
+}
+
+// readJSON 从 WebSocket 读取一条 JSON 消息。
+func readJSON(t *testing.T, conn *websocket.Conn) map[string]any {
+	t.Helper()
+
+	conn.SetReadDeadline(time.Now().Add(5 * time.Second))
+	var msg map[string]any
+	err := conn.ReadJSON(&msg)
+	require.NoError(t, err, "读取 WebSocket 消息失败")
+	return msg
+}
+
+// --- 测试用例 ---
+
+// TestWS_Connected 验证连接建立后收到 connected 消息。
+func TestWS_Connected(t *testing.T) {
+	srv, wsURL := setupTestServer(t, &MockOrchestrator{})
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+
+	msg := readJSON(t, conn)
+	assert.Equal(t, "connected", msg["type"])
+	assert.NotEmpty(t, msg["session_id"])
+	assert.Equal(t, "0.1.0", msg["server_version"])
+}
+
+// TestWS_PingPong 验证 ping/pong 心跳。
+func TestWS_PingPong(t *testing.T) {
+	srv, wsURL := setupTestServer(t, &MockOrchestrator{})
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+
+	// 读取 connected 消息
+	_ = readJSON(t, conn)
+
+	// 发送 ping
+	err := conn.WriteJSON(map[string]string{"type": "ping"})
+	require.NoError(t, err)
+
+	// 读取 pong
+	msg := readJSON(t, conn)
+	assert.Equal(t, "pong", msg["type"])
+}
+
+// TestWS_QueryFullFlow 验证完整的 query → stt_result → llm_chunk → tts_audio → llm_done 流程。
+func TestWS_QueryFullFlow(t *testing.T) {
+	audioB64 := base64.StdEncoding.EncodeToString([]byte("fake-audio-data"))
+	imageB64 := base64.StdEncoding.EncodeToString([]byte("fake-image-data"))
+
+	mock := &MockOrchestrator{
+		STTResult:  "你好，世界",
+		LLMDeltas:  []string{"你好", "，世界！"},
+		TTSAudios:  []string{base64.StdEncoding.EncodeToString([]byte("mp3-data-1")), base64.StdEncoding.EncodeToString([]byte("mp3-data-2"))},
+	}
+
+	srv, wsURL := setupTestServer(t, mock)
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+
+	// 1. 读取 connected
+	connected := readJSON(t, conn)
+	assert.Equal(t, "connected", connected["type"])
+	sessionID := connected["session_id"].(string)
+	assert.NotEmpty(t, sessionID)
+
+	// 2. 发送 query
+	queryMsg := models.WsQuery{
+		Type:      "query",
+		RequestID: "req-test-001",
+		Image:     imageB64,
+		Audio:     audioB64,
+		MimeType:  "audio/pcm",
+	}
+	err := conn.WriteJSON(queryMsg)
+	require.NoError(t, err)
+
+	// 3. 读取 stt_result
+	sttResult := readJSON(t, conn)
+	assert.Equal(t, "stt_result", sttResult["type"])
+	assert.Equal(t, "req-test-001", sttResult["request_id"])
+	assert.Equal(t, "你好，世界", sttResult["text"])
+	assert.Equal(t, true, sttResult["is_final"])
+
+	// 4. 读取 llm_chunk 消息
+	chunk1 := readJSON(t, conn)
+	assert.Equal(t, "llm_chunk", chunk1["type"])
+	assert.Equal(t, "req-test-001", chunk1["request_id"])
+	assert.Equal(t, "你好", chunk1["delta"])
+	assert.Equal(t, "assistant", chunk1["role"])
+
+	chunk2 := readJSON(t, conn)
+	assert.Equal(t, "llm_chunk", chunk2["type"])
+	assert.Equal(t, "，世界！", chunk2["delta"])
+
+	// 5. 读取 tts_audio 消息
+	tts1 := readJSON(t, conn)
+	assert.Equal(t, "tts_audio", tts1["type"])
+	assert.Equal(t, "req-test-001", tts1["request_id"])
+	assert.NotEmpty(t, tts1["audio"])
+	assert.Equal(t, "audio/mp3", tts1["mime_type"])
+	assert.Equal(t, false, tts1["is_last"])
+
+	tts2 := readJSON(t, conn)
+	assert.Equal(t, "tts_audio", tts2["type"])
+	assert.Equal(t, true, tts2["is_last"])
+
+	// 6. 读取 llm_done
+	llmDone := readJSON(t, conn)
+	assert.Equal(t, "llm_done", llmDone["type"])
+	assert.Equal(t, "req-test-001", llmDone["request_id"])
+	assert.Equal(t, "你好，世界！", llmDone["full_text"])
+	assert.Equal(t, "gpt-4o", llmDone["model"])
+	assert.NotNil(t, llmDone["latency_ms"])
+}
+
+// TestWS_QuerySTTOnly 验证只有 STT 结果、无 LLM 输出的场景。
+func TestWS_QuerySTTOnly(t *testing.T) {
+	audioB64 := base64.StdEncoding.EncodeToString([]byte("audio"))
+
+	mock := &MockOrchestrator{
+		STTResult: "测试语音",
+		// LLMDeltas 为空 → 不发送 llm_chunk
+		// TTSAudios 为空 → 不发送 tts_audio
+	}
+
+	srv, wsURL := setupTestServer(t, mock)
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+	_ = readJSON(t, conn) // connected
+
+	err := conn.WriteJSON(models.WsQuery{
+		Type:      "query",
+		RequestID: "req-stt-only",
+		Audio:     audioB64,
+	})
+	require.NoError(t, err)
+
+	// 应收到 stt_result
+	stt := readJSON(t, conn)
+	assert.Equal(t, "stt_result", stt["type"])
+	assert.Equal(t, "测试语音", stt["text"])
+
+	// 应收到 llm_done（即使没有 chunk）
+	done := readJSON(t, conn)
+	assert.Equal(t, "llm_done", done["type"])
+	assert.Equal(t, "", done["full_text"])
+}
+
+// TestWS_UnknownMessageType 验证未知消息类型返回 error。
+func TestWS_UnknownMessageType(t *testing.T) {
+	srv, wsURL := setupTestServer(t, &MockOrchestrator{})
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+	_ = readJSON(t, conn) // connected
+
+	err := conn.WriteJSON(map[string]string{"type": "unknown_type"})
+	require.NoError(t, err)
+
+ errMsg := readJSON(t, conn)
+	assert.Equal(t, "error", errMsg["type"])
+	assert.Equal(t, "INVALID_MESSAGE", errMsg["code"])
+	assert.Contains(t, errMsg["message"], "unknown message type")
+}
+
+// TestWS_InvalidJSON 验证无效 JSON 返回 error。
+func TestWS_InvalidJSON(t *testing.T) {
+	srv, wsURL := setupTestServer(t, &MockOrchestrator{})
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+	_ = readJSON(t, conn) // connected
+
+	err := conn.WriteMessage(websocket.TextMessage, []byte("not-json"))
+	require.NoError(t, err)
+
+	errMsg := readJSON(t, conn)
+	assert.Equal(t, "error", errMsg["type"])
+	assert.Equal(t, "INVALID_MESSAGE", errMsg["code"])
+}
+
+// TestWS_MultipleQueries 验证同一连接上可以发送多次 query。
+func TestWS_MultipleQueries(t *testing.T) {
+	mock := &MockOrchestrator{
+		STTResult: "识别结果",
+		LLMDeltas: []string{"回复"},
+	}
+
+	srv, wsURL := setupTestServer(t, mock)
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+	_ = readJSON(t, conn) // connected
+
+	audioB64 := base64.StdEncoding.EncodeToString([]byte("audio"))
+
+	for i := 0; i < 3; i++ {
+		reqID := "req-multi-" + string(rune('0'+i))
+		err := conn.WriteJSON(models.WsQuery{
+			Type:      "query",
+			RequestID: reqID,
+			Audio:     audioB64,
+		})
+		require.NoError(t, err)
+
+		// 每次应收到完整的响应序列
+		stt := readJSON(t, conn)
+		assert.Equal(t, "stt_result", stt["type"], "第 %d 次 query", i+1)
+
+		chunk := readJSON(t, conn)
+		assert.Equal(t, "llm_chunk", chunk["type"], "第 %d 次 query", i+1)
+
+		done := readJSON(t, conn)
+		assert.Equal(t, "llm_done", done["type"], "第 %d 次 query", i+1)
+	}
+}
+
+// TestWS_Interrupt 验证 interrupt 取消正在进行的请求。
+func TestWS_Interrupt(t *testing.T) {
+	// 使用较长延迟模拟慢请求
+	mock := &MockOrchestrator{
+		STTResult: "识别文本",
+		LLMDeltas: []string{"第一句", "第二句", "第三句", "第四句", "第五句"},
+		Delay:     200 * time.Millisecond,
+	}
+
+	srv, wsURL := setupTestServer(t, mock)
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+	_ = readJSON(t, conn) // connected
+
+	audioB64 := base64.StdEncoding.EncodeToString([]byte("audio"))
+
+	// 发送 query
+	err := conn.WriteJSON(models.WsQuery{
+		Type:      "query",
+		RequestID: "req-interrupt",
+		Audio:     audioB64,
+	})
+	require.NoError(t, err)
+
+	// 收到 stt_result
+	stt := readJSON(t, conn)
+	assert.Equal(t, "stt_result", stt["type"])
+
+	// 收到第一个 llm_chunk
+	chunk1 := readJSON(t, conn)
+	assert.Equal(t, "llm_chunk", chunk1["type"])
+
+	// 发送 interrupt
+	err = conn.WriteJSON(map[string]string{"type": "interrupt"})
+	require.NoError(t, err)
+
+	// 等待 interrupt 生效
+	time.Sleep(500 * time.Millisecond)
+
+	// 验证连接仍然存活（可以发 ping 收 pong）
+	require.NoError(t, conn.WriteJSON(map[string]string{"type": "ping"}))
+
+	var pong map[string]any
+	conn.SetReadDeadline(time.Now().Add(5 * time.Second))
+	require.NoError(t, conn.ReadJSON(&pong), "interrupt 后连接应仍存活")
+	assert.Equal(t, "pong", pong["type"])
+}
+
+// TestWS_DisconnectCleanup 验证断开连接时清理资源。
+func TestWS_DisconnectCleanup(t *testing.T) {
+	// 使用较长延迟模拟慢请求
+	mock := &MockOrchestrator{
+		STTResult: "识别文本",
+		LLMDeltas: []string{"长回复第一部分", "长回复第二部分"},
+		Delay:     500 * time.Millisecond,
+	}
+
+	srv, wsURL := setupTestServer(t, mock)
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+	_ = readJSON(t, conn) // connected
+
+	audioB64 := base64.StdEncoding.EncodeToString([]byte("audio"))
+
+	// 发送 query
+	err := conn.WriteJSON(models.WsQuery{
+		Type:      "query",
+		RequestID: "req-disconnect",
+		Audio:     audioB64,
+	})
+	require.NoError(t, err)
+
+	// 收到 stt_result
+	stt := readJSON(t, conn)
+	assert.Equal(t, "stt_result", stt["type"])
+
+	// 关闭连接（模拟客户端断开）
+	conn.Close()
+
+	// 等待一小段时间让服务器处理断开
+	time.Sleep(300 * time.Millisecond)
+
+	// 如果没有 panic 或 goroutine 泄漏，测试通过
+	// （Go test 的 -race 检测器会捕获数据竞争）
+}
+
+// TestWS_SessionCreated 验证每次连接都创建新会话。
+func TestWS_SessionCreated(t *testing.T) {
+	srv, wsURL := setupTestServer(t, &MockOrchestrator{})
+	defer srv.Close()
+
+	// 第一次连接
+	conn1 := connectWS(t, wsURL)
+	msg1 := readJSON(t, conn1)
+	sid1 := msg1["session_id"].(string)
+	conn1.Close()
+
+	time.Sleep(100 * time.Millisecond)
+
+	// 第二次连接
+	conn2 := connectWS(t, wsURL)
+	sid2 := readJSON(t, conn2)["session_id"].(string)
+
+	assert.NotEmpty(t, sid1)
+	assert.NotEmpty(t, sid2)
+	assert.NotEqual(t, sid1, sid2, "两次连接应创建不同的会话")
+}
+
+// TestWS_QueryWithoutImage 验证不带图片的 query。
+func TestWS_QueryWithoutImage(t *testing.T) {
+	mock := &MockOrchestrator{
+		STTResult: "纯语音输入",
+		LLMDeltas: []string{"收到"},
+	}
+
+	srv, wsURL := setupTestServer(t, mock)
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+	_ = readJSON(t, conn) // connected
+
+	audioB64 := base64.StdEncoding.EncodeToString([]byte("audio"))
+
+	err := conn.WriteJSON(models.WsQuery{
+		Type:      "query",
+		RequestID: "req-no-image",
+		Audio:     audioB64,
+		// Image 为空
+	})
+	require.NoError(t, err)
+
+	stt := readJSON(t, conn)
+	assert.Equal(t, "stt_result", stt["type"])
+	assert.Equal(t, "纯语音输入", stt["text"])
+
+	chunk := readJSON(t, conn)
+	assert.Equal(t, "llm_chunk", chunk["type"])
+
+	done := readJSON(t, conn)
+	assert.Equal(t, "llm_done", done["type"])
+}
+
+// TestWS_QueryWithTTSDisabled 验证 TTS 未启用时不应收到 tts_audio。
+func TestWS_QueryWithTTSDisabled(t *testing.T) {
+	// MockOrchestrator 的 TTSAudios 为空 → 不发送 tts_audio
+	mock := &MockOrchestrator{
+		STTResult: "语音",
+		LLMDeltas: []string{"回复"},
+		// TTSAudios 留空
+	}
+
+	srv, wsURL := setupTestServer(t, mock)
+	defer srv.Close()
+
+	conn := connectWS(t, wsURL)
+	_ = readJSON(t, conn) // connected
+
+	audioB64 := base64.StdEncoding.EncodeToString([]byte("audio"))
+
+	err := conn.WriteJSON(models.WsQuery{
+		Type:      "query",
+		RequestID: "req-no-tts",
+		Audio:     audioB64,
+	})
+	require.NoError(t, err)
+
+	stt := readJSON(t, conn)
+	assert.Equal(t, "stt_result", stt["type"])
+
+	chunk := readJSON(t, conn)
+	assert.Equal(t, "llm_chunk", chunk["type"])
+
+	done := readJSON(t, conn)
+	assert.Equal(t, "llm_done", done["type"])
+
+	// 不应有 tts_audio 消息；设置短超时验证
+	conn.SetReadDeadline(time.Now().Add(200 * time.Millisecond))
+	var extra map[string]any
+	err = conn.ReadJSON(&extra)
+	assert.Error(t, err, "不应有额外消息")
+}