diff --git a/components/lib/treetable/treetable.d.ts b/components/lib/treetable/treetable.d.ts
index ed342b389b..42934d2edb 100644
--- a/components/lib/treetable/treetable.d.ts
+++ b/components/lib/treetable/treetable.d.ts
@@ -344,7 +344,7 @@ interface TreeTableSelectionKeysType {
     /**
      * Extra options.
      */
-    [key: string]: boolean | TreeTableCheckboxSelectionKeyType | undefined;
+    [key: string]: boolean | string | TreeTableCheckboxSelectionKeyType | undefined;
 }
 
 /**