diff --git a/MdeModulePkg/Bus/Pci/UhciDxe/UsbHcMem.c b/MdeModulePkg/Bus/Pci/UhciDxe/UsbHcMem.c
index c3d46f60bed5..3794f888e132 100644
--- a/MdeModulePkg/Bus/Pci/UhciDxe/UsbHcMem.c
+++ b/MdeModulePkg/Bus/Pci/UhciDxe/UsbHcMem.c
@@ -250,6 +250,11 @@ UsbHcGetPciAddressForHostMem (
   }
 
   ASSERT ((Block != NULL));
+
+  if (Block == NULL) {
+    return 0;
+  }
+
   //
   // calculate the pci memory address for host memory address.
   //
@@ -536,6 +541,10 @@ UsbHcFreeMem (
   //
   ASSERT (Block != NULL);
 
+  if (Block == NULL) {
+    return;
+  }
+
   //
   // Release the current memory block if it is empty and not the head
   //