diff --git a/src/frontend/src/binder/mod.rs b/src/frontend/src/binder/mod.rs
index 73198d78a66cd..e81324254da67 100644
--- a/src/frontend/src/binder/mod.rs
+++ b/src/frontend/src/binder/mod.rs
@@ -116,11 +116,12 @@ pub struct Binder {
 
     param_types: ParameterTypes,
 
-    /// The mapping from sql udf parameters to ast expressions
+    /// The mapping from `sql udf parameters`` to `ast expressions`
     /// Note: The expressions are constructed during runtime, correspond to the actual users' input
     udf_context: HashMap<String, AstExpr>,
 
     /// The mapping from `function name` to `calling times`
+    /// Record the calling times for every sql udf during the binding phase
     udf_recursive_context: HashMap<String, i32>,
 }