diff --git a/modules/audio/proto/audio_event.proto b/modules/audio/proto/audio_event.proto
index 5873d2e2c727af4e7882665489cd1eb4c96bb756..2b491c651c47e17801a02bbbbb6957d7d0efa982 100644
--- a/modules/audio/proto/audio_event.proto
+++ b/modules/audio/proto/audio_event.proto
@@ -9,4 +9,5 @@ message AudioEvent {
   optional apollo.common.Header header = 1;
   optional int32 id = 2;  // obstacle ID.
   optional apollo.audio.MovingResult moving_result = 3 [default = UNKNOWN];
+  optional bool siren_is_on = 4;
 }