diff --git a/docs/zh/07-develop/09-udf.md b/docs/zh/07-develop/09-udf.md
index 92f5d2a857ec3106c53258adda2a1aaaf0b3bb4c..e43275d5e04818eff8ed0eddf76bd7c768b315f5 100644
--- a/docs/zh/07-develop/09-udf.md
+++ b/docs/zh/07-develop/09-udf.md
@@ -303,7 +303,7 @@ def start() -> bytes:
 def reduce(inputs: datablock, buf: bytes) -> bytes
     # deserialize buf to state
     # reduce the inputs and state into new_state. 
-    # use inputs.data(i,j) to access python ojbect of location(i,j)
+    # use inputs.data(i,j) to access python object of location(i,j)
     # serialize new_state into new_state_bytes
     return new_state_bytes   
 def finish(buf: bytes) -> output_type: