diff --git a/campusapis/teaching/v1/teaching.proto b/campusapis/teaching/v1/teaching.proto
index 24d36ed..c2ef77e 100644
--- a/campusapis/teaching/v1/teaching.proto
+++ b/campusapis/teaching/v1/teaching.proto
@@ -490,7 +490,7 @@ message GetUnusedClassroomsRequest {
   //节次
   int32 section = 5;
   //教学楼
-  int32 buildingID = 6;
+  string buildingID = 6;
 }
 
 message GetClassroomsResponse {