diff --git a/frontend/src/components/pages/AssistantPage.tsx b/frontend/src/components/pages/AssistantPage.tsx
index 49a9eca..39dbde7 100644
--- a/frontend/src/components/pages/AssistantPage.tsx
+++ b/frontend/src/components/pages/AssistantPage.tsx
@@ -1838,7 +1838,7 @@ function DebugVoicePanel({
     messages,
     audioInputs,
     selectedDeviceId,
-    setSelectedDeviceId,
+    selectDevice,
     sendText,
     connect,
     disconnect,
@@ -1868,7 +1868,7 @@ function DebugVoicePanel({
             assistantId={assistantId}
             audioInputs={audioInputs}
             selectedDeviceId={selectedDeviceId}
-            setSelectedDeviceId={setSelectedDeviceId}
+            selectDevice={selectDevice}
             connect={connect}
             disconnect={disconnect}
           />
@@ -1941,9 +1941,8 @@ function DebugVoicePanel({
             <Select
               value={selectedDeviceId || "default"}
               onValueChange={(value) =>
-                setSelectedDeviceId(value === "default" ? "" : value)
+                selectDevice(value === "default" ? "" : value)
               }
-              disabled={recording}
             >
               <SelectTrigger
                 size="sm"
@@ -2044,7 +2043,7 @@ function VoiceSessionControls({
   assistantId,
   audioInputs,
   selectedDeviceId,
-  setSelectedDeviceId,
+  selectDevice,
   connect,
   disconnect,
 }: {
@@ -2054,7 +2053,7 @@ function VoiceSessionControls({
   assistantId: string | null;
   audioInputs: MediaDeviceInfo[];
   selectedDeviceId: string;
-  setSelectedDeviceId: (deviceId: string) => void;
+  selectDevice: (deviceId: string) => void;
   connect: () => Promise<void>;
   disconnect: () => void;
 }) {
@@ -2096,9 +2095,8 @@ function VoiceSessionControls({
         <Select
           value={selectedDeviceId || "default"}
           onValueChange={(value) =>
-            setSelectedDeviceId(value === "default" ? "" : value)
+            selectDevice(value === "default" ? "" : value)
           }
-          disabled={recording}
         >
           <SelectTrigger
             size="sm"
diff --git a/frontend/src/hooks/use-voice-preview.ts b/frontend/src/hooks/use-voice-preview.ts
index 052e319..650a8f3 100644
--- a/frontend/src/hooks/use-voice-preview.ts
+++ b/frontend/src/hooks/use-voice-preview.ts
@@ -373,6 +373,56 @@ export function useVoicePreview(assistantId: string | null) {
     }
   }, [assistantId, fail, refreshDevices]);
 
+  // 选择麦克风:更新选择;若会话正在发送麦克风音频,则用 WebRTC replaceTrack
+  // 热切换轨道(无需重新协商),并把波形可视化重新接到新流。
+  // 未连接时仅记下选择,留待下次 connect 生效。
+  const selectDevice = useCallback(
+    async (deviceId: string) => {
+      setSelectedDeviceId(deviceId);
+      selectedDeviceIdRef.current = deviceId;
+
+      const pc = pcRef.current;
+      if (!pc) return;
+      // 只有本就在发送麦克风音频(存在 audio sender 轨道)时才热切换;
+      // 仅收听模式下加麦克风需重新协商,这里不处理,留到下次连接。
+      const sender = pc
+        .getSenders()
+        .find((s) => s.track?.kind === "audio");
+      if (!sender) return;
+
+      try {
+        const audioConstraints: MediaTrackConstraints = {
+          echoCancellation: true,
+          noiseSuppression: true,
+          autoGainControl: true,
+        };
+        if (deviceId) audioConstraints.deviceId = { exact: deviceId };
+        const newStream = await navigator.mediaDevices.getUserMedia({
+          audio: audioConstraints,
+        });
+        // 切换期间可能已断开,丢弃刚拿到的流
+        if (pcRef.current !== pc) {
+          newStream.getTracks().forEach((t) => t.stop());
+          return;
+        }
+        const newTrack = newStream.getAudioTracks()[0];
+        if (!newTrack) {
+          newStream.getTracks().forEach((t) => t.stop());
+          return;
+        }
+        await sender.replaceTrack(newTrack);
+        // 旧轨道停掉,新流替换(波形/分析器随 localStream 变化自动重连)
+        localStreamRef.current?.getTracks().forEach((t) => t.stop());
+        localStreamRef.current = newStream;
+        setLocalStream(newStream);
+        setMicWarning(null);
+      } catch (mediaError) {
+        setMicWarning(microphoneErrorMessage(mediaError));
+      }
+    },
+    [],
+  );
+
   // 发送文字消息:后端先打断当前播报,再按用户输入触发新回复。
   // 成功返回 true;通道未就绪(未开始对话/连接中)返回 false。
   const sendText = useCallback((text: string): boolean => {
@@ -396,6 +446,7 @@ export function useVoicePreview(assistantId: string | null) {
     audioInputs,
     selectedDeviceId,
     setSelectedDeviceId,
+    selectDevice,
     sendText,
     connect,
     disconnect,