diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc b/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
index 62762308e2..976af1f78e 100644
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpEqu.inc
@@ -33,7 +33,7 @@ GdtrLocation                  equ        LockLocation + 10h
 IdtrLocation                  equ        LockLocation + 16h
 BufferStartLocation           equ        LockLocation + 1Ch
 ModeOffsetLocation            equ        LockLocation + 20h
-NumApsExecutingLocation       equ        LockLocation + 24h
+ApIndexLocation               equ        LockLocation + 24h
 CodeSegmentLocation           equ        LockLocation + 28h
 DataSegmentLocation           equ        LockLocation + 2Ch
 EnableExecuteDisableLocation  equ        LockLocation + 30h
diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
index 52363e6e08..1b9c6a62f8 100644
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
@@ -130,7 +130,7 @@ TestLock:
     jz         TestLock
 
     mov        ecx, esi
-    add        ecx, NumApsExecutingLocation
+    add        ecx, ApIndexLocation
     inc        dword [ecx]
     mov        ebx, [ecx]
 
@@ -200,7 +200,7 @@ CProcedureInvoke:
     mov        eax, ASM_PFX(InitializeFloatingPointUnits)
     call       eax               ; Call assembly function to initialize FPU per UEFI spec
 
-    push       ebx               ; Push NumApsExecuting
+    push       ebx               ; Push ApIndex
     mov        eax, esi
     add        eax, LockLocation
     push       eax               ; push address of exchange info data buffer
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index f3ee6d4436..db923c9917 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -542,7 +542,7 @@ VOID
 EFIAPI
 ApWakeupFunction (
   IN MP_CPU_EXCHANGE_INFO      *ExchangeInfo,
-  IN UINTN                     NumApsExecuting
+  IN UINTN                     ApIndex
   )
 {
   CPU_MP_DATA                *CpuMpData;
@@ -574,7 +574,7 @@ ApWakeupFunction (
       // Add CPU number
       //
       InterlockedIncrement ((UINT32 *) &CpuMpData->CpuCount);
-      ProcessorNumber = NumApsExecuting;
+      ProcessorNumber = ApIndex;
       //
       // This is first time AP wakeup, get BIST information from AP stack
       //
@@ -764,7 +764,7 @@ FillExchangeInfoData (
   ExchangeInfo->Cr3             = AsmReadCr3 ();
 
   ExchangeInfo->CFunction       = (UINTN) ApWakeupFunction;
-  ExchangeInfo->NumApsExecuting = 0;
+  ExchangeInfo->ApIndex         = 0;
   ExchangeInfo->InitFlag        = (UINTN) CpuMpData->InitFlag;
   ExchangeInfo->CpuInfo         = (CPU_INFO_IN_HOB *) (UINTN) CpuMpData->CpuInfoInHob;
   ExchangeInfo->CpuMpData       = CpuMpData;
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index 84ae24f88d..e41d2db94a 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -169,7 +169,7 @@ typedef struct {
   IA32_DESCRIPTOR       IdtrProfile;
   UINTN                 BufferStart;
   UINTN                 ModeOffset;
-  UINTN                 NumApsExecuting;
+  UINTN                 ApIndex;
   UINTN                 CodeSegment;
   UINTN                 DataSegment;
   UINTN                 EnableExecuteDisable;
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc b/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
index 5b2529b5cb..114f4e0a7d 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
+++ b/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
@@ -33,7 +33,7 @@ GdtrLocation                  equ        LockLocation + 20h
 IdtrLocation                  equ        LockLocation + 2Ah
 BufferStartLocation           equ        LockLocation + 34h
 ModeOffsetLocation            equ        LockLocation + 3Ch
-NumApsExecutingLocation       equ        LockLocation + 44h
+ApIndexLocation               equ        LockLocation + 44h
 CodeSegmentLocation           equ        LockLocation + 4Ch
 DataSegmentLocation           equ        LockLocation + 54h
 EnableExecuteDisableLocation  equ        LockLocation + 5Ch
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
index 0b14a53466..4ada6493d4 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
@@ -134,7 +134,7 @@ TestLock:
     cmp        rax, NotVacantFlag
     jz         TestLock
 
-    lea        ecx, [esi + NumApsExecutingLocation]
+    lea        ecx, [esi + ApIndexLocation]
     inc        dword [ecx]
     mov        ebx, [ecx]
 
@@ -206,7 +206,7 @@ CProcedureInvoke:
     call       rax               ; Call assembly function to initialize FPU per UEFI spec
     add        rsp, 20h
 
-    mov        edx, ebx          ; edx is NumApsExecuting
+    mov        edx, ebx          ; edx is ApIndex
     mov        ecx, esi
     add        ecx, LockLocation ; rcx is address of exchange info data buffer