diff --git a/x/register/keeper/keeper.go b/x/register/keeper/keeper.go
index d07d1822..c79ecd66 100644
--- a/x/register/keeper/keeper.go
+++ b/x/register/keeper/keeper.go
@@ -19,25 +19,22 @@ import (
 	regtypes "github.com/stratosnet/stratos-chain/x/register/types"
 )
 
-var (
-	metaNodeBitMapIndexCacheStatus = types.CACHE_DIRTY
-	cacheMutex                     sync.RWMutex
-)
-
 // Keeper of the register store
 type Keeper struct {
-	storeKey                 sdk.StoreKey
-	cdc                      codec.Codec
-	paramSpace               paramtypes.Subspace
-	accountKeeper            types.AccountKeeper
-	bankKeeper               types.BankKeeper
-	distrKeeper              types.DistrKeeper
-	hooks                    types.RegisterHooks
-	resourceNodeCache        map[string]cachedResourceNode
-	resourceNodeCacheList    *list.List
-	metaNodeCache            map[string]cachedMetaNode
-	metaNodeCacheList        *list.List
-	metaNodeBitMapIndexCache map[string]int
+	storeKey                       sdk.StoreKey
+	cdc                            codec.Codec
+	paramSpace                     paramtypes.Subspace
+	accountKeeper                  types.AccountKeeper
+	bankKeeper                     types.BankKeeper
+	distrKeeper                    types.DistrKeeper
+	hooks                          types.RegisterHooks
+	resourceNodeCache              map[string]cachedResourceNode
+	resourceNodeCacheList          *list.List
+	metaNodeCache                  map[string]cachedMetaNode
+	metaNodeCacheList              *list.List
+	metaNodeBitMapIndexCache       map[string]int
+	metaNodeBitMapIndexCacheStatus types.CacheStatus
+	cacheMutex                     sync.RWMutex
 }
 
 // NewKeeper creates a register keeper
@@ -45,18 +42,20 @@ func NewKeeper(cdc codec.Codec, key sdk.StoreKey, paramSpace paramtypes.Subspace
 	accountKeeper types.AccountKeeper, bankKeeper types.BankKeeper, distrKeeper types.DistrKeeper) Keeper {
 
 	keeper := Keeper{
-		storeKey:                 key,
-		cdc:                      cdc,
-		paramSpace:               paramSpace.WithKeyTable(types.ParamKeyTable()),
-		accountKeeper:            accountKeeper,
-		bankKeeper:               bankKeeper,
-		distrKeeper:              distrKeeper,
-		hooks:                    nil,
-		resourceNodeCache:        make(map[string]cachedResourceNode, resourceNodeCacheSize),
-		resourceNodeCacheList:    list.New(),
-		metaNodeCache:            make(map[string]cachedMetaNode, metaNodeCacheSize),
-		metaNodeCacheList:        list.New(),
-		metaNodeBitMapIndexCache: make(map[string]int),
+		storeKey:                       key,
+		cdc:                            cdc,
+		paramSpace:                     paramSpace.WithKeyTable(types.ParamKeyTable()),
+		accountKeeper:                  accountKeeper,
+		bankKeeper:                     bankKeeper,
+		distrKeeper:                    distrKeeper,
+		hooks:                          nil,
+		resourceNodeCache:              make(map[string]cachedResourceNode, resourceNodeCacheSize),
+		resourceNodeCacheList:          list.New(),
+		metaNodeCache:                  make(map[string]cachedMetaNode, metaNodeCacheSize),
+		metaNodeCacheList:              list.New(),
+		metaNodeBitMapIndexCache:       make(map[string]int),
+		metaNodeBitMapIndexCacheStatus: types.CACHE_DIRTY,
+		cacheMutex:                     sync.RWMutex{},
 	}
 	return keeper
 }
diff --git a/x/register/keeper/meta_node.go b/x/register/keeper/meta_node.go
index e3bb8c33..014852ba 100644
--- a/x/register/keeper/meta_node.go
+++ b/x/register/keeper/meta_node.go
@@ -556,8 +556,8 @@ func (k Keeper) OwnMetaNode(ctx sdk.Context, ownerAddr sdk.AccAddress, p2pAddr s
 func (k Keeper) GetMetaNodeBitMapIndex(ctx sdk.Context, networkAddr stratos.SdsAddress) (index int, err error) {
 	k.UpdateMetaNodeBitMapIdxCache(ctx)
 
-	cacheMutex.RLock()
-	defer cacheMutex.RUnlock()
+	k.cacheMutex.RLock()
+	defer k.cacheMutex.RUnlock()
 
 	index, ok := k.metaNodeBitMapIndexCache[networkAddr.String()]
 	if !ok {
@@ -571,29 +571,30 @@ func (k Keeper) GetMetaNodeBitMapIndex(ctx sdk.Context, networkAddr stratos.SdsA
 }
 
 func (k Keeper) AddMetaNodeToBitMapIdxCache(networkAddr stratos.SdsAddress) {
-	cacheMutex.Lock()
-	defer cacheMutex.Unlock()
+	k.cacheMutex.Lock()
+	defer k.cacheMutex.Unlock()
 
 	k.metaNodeBitMapIndexCache[networkAddr.String()] = -1
-	metaNodeBitMapIndexCacheStatus = types.CACHE_DIRTY
+	k.metaNodeBitMapIndexCacheStatus = types.CACHE_DIRTY
 }
 
 func (k Keeper) RemoveMetaNodeFromBitMapIdxCache(networkAddr stratos.SdsAddress) {
-	cacheMutex.Lock()
-	defer cacheMutex.Unlock()
+	k.cacheMutex.Lock()
+	defer k.cacheMutex.Unlock()
 
 	delete(k.metaNodeBitMapIndexCache, networkAddr.String())
-	metaNodeBitMapIndexCacheStatus = types.CACHE_DIRTY
+	k.metaNodeBitMapIndexCacheStatus = types.CACHE_DIRTY
 }
 
 func (k Keeper) UpdateMetaNodeBitMapIdxCache(ctx sdk.Context) {
-	cacheMutex.Lock()
-	defer cacheMutex.Unlock()
+	k.cacheMutex.Lock()
 
-	if metaNodeBitMapIndexCacheStatus == types.CACHE_NOT_DIRTY {
+	if k.metaNodeBitMapIndexCacheStatus == types.CACHE_NOT_DIRTY {
+		k.cacheMutex.Unlock()
 		return
 	}
 	if len(k.metaNodeBitMapIndexCache) == 0 {
+		k.cacheMutex.Unlock()
 		k.ReloadMetaNodeBitMapIdxCache(ctx)
 		return
 	}
@@ -608,14 +609,15 @@ func (k Keeper) UpdateMetaNodeBitMapIdxCache(ctx sdk.Context) {
 	for index, key := range keys {
 		k.metaNodeBitMapIndexCache[key] = index
 	}
-	metaNodeBitMapIndexCacheStatus = types.CACHE_NOT_DIRTY
+	k.metaNodeBitMapIndexCacheStatus = types.CACHE_NOT_DIRTY
+	k.cacheMutex.Unlock()
 }
 
 func (k Keeper) ReloadMetaNodeBitMapIdxCache(ctx sdk.Context) {
-	cacheMutex.Lock()
-	defer cacheMutex.Unlock()
+	k.cacheMutex.Lock()
+	defer k.cacheMutex.Unlock()
 
-	if metaNodeBitMapIndexCacheStatus == types.CACHE_NOT_DIRTY {
+	if k.metaNodeBitMapIndexCacheStatus == types.CACHE_NOT_DIRTY {
 		return
 	}
 	keys := make([]string, 0)
@@ -637,5 +639,5 @@ func (k Keeper) ReloadMetaNodeBitMapIdxCache(ctx sdk.Context) {
 	for index, key := range keys {
 		k.metaNodeBitMapIndexCache[key] = index
 	}
-	metaNodeBitMapIndexCacheStatus = types.CACHE_NOT_DIRTY
+	k.metaNodeBitMapIndexCacheStatus = types.CACHE_NOT_DIRTY
 }