diff --git a/MdeModulePkg/Core/Pei/Dependency/Dependency.h b/MdeModulePkg/Core/Pei/Dependency/Dependency.h
index c15fd0d816..ff99783ac2 100644
--- a/MdeModulePkg/Core/Pei/Dependency/Dependency.h
+++ b/MdeModulePkg/Core/Pei/Dependency/Dependency.h
@@ -17,7 +17,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #define _PEI_DEPENDENCY_H_
 
 
-#define MAX_GRAMMAR_SIZE  256
+#define MAX_GRAMMAR_SIZE  64
 
 //
 // type definitions