diff --git a/src/pages/oj/components/CodeMirror.vue b/src/pages/oj/components/CodeMirror.vue
index a6f885d27..770c71813 100644
--- a/src/pages/oj/components/CodeMirror.vue
+++ b/src/pages/oj/components/CodeMirror.vue
@@ -101,6 +101,7 @@
           mode[lang.name] = lang.content_type
         })
         this.mode = mode
+        this.editor.setOption('mode', this.mode[this.language])
       })
       this.editor.focus()
     },