diff --git a/MdeModulePkg/Universal/DisplayEngineDxe/ProcessOptions.c b/MdeModulePkg/Universal/DisplayEngineDxe/ProcessOptions.c
index f55fb2e263..c074f4b4a3 100644
--- a/MdeModulePkg/Universal/DisplayEngineDxe/ProcessOptions.c
+++ b/MdeModulePkg/Universal/DisplayEngineDxe/ProcessOptions.c
@@ -21,6 +21,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
   Concatenate a narrow string to another string.
 
   @param Destination The destination string.
+  @param DestMax     The Max length of destination string.
   @param Source      The source string. The string to be concatenated.
                      to the end of Destination.