diff --git a/doc/ui/cmd_argument/detail_introduction.md b/doc/ui/cmd_argument/detail_introduction.md
index 0628289dbd683222e6a50b87fe7224bcf9c40964..1ff4bdbaa3a7b626f9d8c48d0e86b7886ab5faeb 100644
--- a/doc/ui/cmd_argument/detail_introduction.md
+++ b/doc/ui/cmd_argument/detail_introduction.md
@@ -110,7 +110,7 @@
   - type: int32 (default: -1).
 
 * `--test_period_while_training`
-  - Run test every so many train batches. If not 0, test log_period batches. If 0, test nothing.
+  - Run test every test_period_while_training batches while doing training. If not 0, test log_period batches. If 0, test nothing.
   - type: int32 (default: 0).
 
 * `--test_wait`