diff --git a/application/src/main/kotlin/tw/waterballsa/gaas/application/usecases/JoinRoomUsecase.kt b/application/src/main/kotlin/tw/waterballsa/gaas/application/usecases/JoinRoomUsecase.kt
index 8b5f323f..19825467 100644
--- a/application/src/main/kotlin/tw/waterballsa/gaas/application/usecases/JoinRoomUsecase.kt
+++ b/application/src/main/kotlin/tw/waterballsa/gaas/application/usecases/JoinRoomUsecase.kt
@@ -9,6 +9,10 @@ import tw.waterballsa.gaas.exceptions.PlatformException
 import tw.waterballsa.gaas.exceptions.enums.PlatformError.PLAYER_JOIN_ROOM_ERROR
 import tw.waterballsa.gaas.exceptions.enums.PlatformError.ROOM_FULL
 import tw.waterballsa.gaas.exceptions.enums.PlatformError.ROOM_PASSWORD_INCORRECT
+import tw.waterballsa.gaas.events.PlayerJoinedRoomEvent
+import tw.waterballsa.gaas.events.PlayerJoinedRoomEvent.Data
+import tw.waterballsa.gaas.events.PlayerJoinedRoomEvent.Data.Player
+import tw.waterballsa.gaas.events.enums.EventMessageType.USER_JOINED
 import javax.inject.Named
 
 @Named
@@ -27,6 +31,9 @@ class JoinRoomUsecase(
             validateRoomPassword(password)
             ensureThatPlayerNotJoinFullRoom()
             joinPlayer(player)
+
+            val playerJoinedRoomEvent = room.joinRoomEvent(player.id.value, player.nickname)
+            eventBus.broadcast(playerJoinedRoomEvent)
         }
     }
 
@@ -57,6 +64,15 @@ class JoinRoomUsecase(
         return roomRepository.update(this)
     }
 
+    private fun Room.joinRoomEvent(
+        playerId: String,
+        nickname: String
+    ) : PlayerJoinedRoomEvent{
+        val user = Player(playerId, nickname)
+        val data = Data(user, roomId!!.value)
+        return PlayerJoinedRoomEvent(USER_JOINED, data)
+    }
+
     data class Request(
         val roomId: String,
         val userIdentity: String,
diff --git a/application/src/main/kotlin/tw/waterballsa/gaas/application/usecases/LeaveRoomUsecase.kt b/application/src/main/kotlin/tw/waterballsa/gaas/application/usecases/LeaveRoomUsecase.kt
index c1db801c..63ec471b 100644
--- a/application/src/main/kotlin/tw/waterballsa/gaas/application/usecases/LeaveRoomUsecase.kt
+++ b/application/src/main/kotlin/tw/waterballsa/gaas/application/usecases/LeaveRoomUsecase.kt
@@ -3,6 +3,11 @@ package tw.waterballsa.gaas.application.usecases
 import tw.waterballsa.gaas.application.eventbus.EventBus
 import tw.waterballsa.gaas.application.repositories.RoomRepository
 import tw.waterballsa.gaas.application.repositories.UserRepository
+import tw.waterballsa.gaas.domain.Room
+import tw.waterballsa.gaas.events.PlayerLeavedRoomEvent
+import tw.waterballsa.gaas.events.PlayerLeavedRoomEvent.Data
+import tw.waterballsa.gaas.events.PlayerLeavedRoomEvent.Data.Player
+import tw.waterballsa.gaas.events.enums.EventMessageType.USER_LEFT
 import javax.inject.Named
 
 @Named
@@ -21,9 +26,21 @@ class LeaveRoomUsecase(
                 room.isEmpty() -> roomRepository.closeRoom(room)
                 else -> roomRepository.leaveRoom(room)
             }
+
+            val playerLeavedRoomEvent = room.leaveRoomEvent(player.id.value, player.nickname)
+            eventBus.broadcast(playerLeavedRoomEvent)
         }
     }
 
+    private fun Room.leaveRoomEvent(
+        playerId: String,
+        nickname: String
+    ) : PlayerLeavedRoomEvent {
+        val user = Player(playerId, nickname)
+        val data = Data(user, roomId!!.value)
+        return PlayerLeavedRoomEvent(USER_LEFT, data)
+    }
+
     data class Request(
         val roomId: String,
         val userIdentity: String,
diff --git a/domain/src/main/kotlin/tw/waterballsa/gaas/events/PlayerJoinedRoomEvent.kt b/domain/src/main/kotlin/tw/waterballsa/gaas/events/PlayerJoinedRoomEvent.kt
new file mode 100644
index 00000000..1b6abe32
--- /dev/null
+++ b/domain/src/main/kotlin/tw/waterballsa/gaas/events/PlayerJoinedRoomEvent.kt
@@ -0,0 +1,18 @@
+package tw.waterballsa.gaas.events
+
+import tw.waterballsa.gaas.events.enums.EventMessageType
+
+data class PlayerJoinedRoomEvent(
+    val type: EventMessageType,
+    val data: Data
+) : DomainEvent() {
+    data class Data(
+        val user: Player,
+        val roomId: String
+    ) {
+        data class Player(
+            val id: String,
+            val nickname: String
+        )
+    }
+}
\ No newline at end of file
diff --git a/domain/src/main/kotlin/tw/waterballsa/gaas/events/PlayerLeavedRoomEvent.kt b/domain/src/main/kotlin/tw/waterballsa/gaas/events/PlayerLeavedRoomEvent.kt
new file mode 100644
index 00000000..b65f3742
--- /dev/null
+++ b/domain/src/main/kotlin/tw/waterballsa/gaas/events/PlayerLeavedRoomEvent.kt
@@ -0,0 +1,18 @@
+package tw.waterballsa.gaas.events
+
+import tw.waterballsa.gaas.events.enums.EventMessageType
+
+data class PlayerLeavedRoomEvent(
+    val type: EventMessageType,
+    val data: Data
+) : DomainEvent() {
+    data class Data(
+        val user: Player,
+        val roomId: String
+    ) {
+        data class Player(
+            val id: String,
+            val nickname: String
+        )
+    }
+}
\ No newline at end of file
diff --git a/domain/src/main/kotlin/tw/waterballsa/gaas/events/enums/EventMessageType.kt b/domain/src/main/kotlin/tw/waterballsa/gaas/events/enums/EventMessageType.kt
index 6101c182..5e69f113 100644
--- a/domain/src/main/kotlin/tw/waterballsa/gaas/events/enums/EventMessageType.kt
+++ b/domain/src/main/kotlin/tw/waterballsa/gaas/events/enums/EventMessageType.kt
@@ -9,4 +9,6 @@ enum class EventMessageType(
     GAME_STARTED("GAME_STARTED"),
     USER_READY("USER_READY"),
     USER_NOT_READY("USER_NOT_READY"),
+    USER_JOINED("USER_JOINED"),
+    USER_LEFT("USER_LEFT"),
 }