diff --git a/MdePkg/MdePkg.spd b/MdePkg/MdePkg.spd
index 774fbf0b0c..89c1f2b2fc 100644
--- a/MdePkg/MdePkg.spd
+++ b/MdePkg/MdePkg.spd
@@ -2330,5 +2330,14 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
       <HelpText>The bitmask of flags that specify the enable/disable of Post
                 Code, Post Code Description.</HelpText>
     </PcdEntry>
+    <PcdEntry>
+      <C_Name>PcdPciExpressBaseAddress</C_Name>
+      <Token>0x0000000a</Token>
+      <TokenSpaceGuidCName>gEfiMdePkgTokenSpaceGuid</TokenSpaceGuidCName>
+      <DatumType>UINT64</DatumType>
+      <ValidUsage>FIXED_AT_BUILD PATCHABLE_IN_MODULE</ValidUsage>
+      <DefaultValue>0xE0000000</DefaultValue>
+      <HelpText>The base address of PCI Express MMIO window.</HelpText>
+    </PcdEntry>
   </PcdDeclarations>
 </PackageSurfaceArea>
\ No newline at end of file