diff --git a/server/statistics/hot_peer.go b/server/statistics/hot_peer.go
index 318de0429614..ce217bac8d51 100644
--- a/server/statistics/hot_peer.go
+++ b/server/statistics/hot_peer.go
@@ -34,7 +34,7 @@ type dimStat struct {
 }
 
 func newDimStat(typ int) *dimStat {
-	reportInterval := RegionHeartBeatReportInterval * time.Second
+	reportInterval := HotStatReportInterval * time.Second
 	return &dimStat{
 		typ:         typ,
 		Rolling:     movingaverage.NewTimeMedian(DefaultAotSize, rollingWindowsSize, reportInterval),
@@ -140,7 +140,7 @@ func (stat *HotPeerStat) Log(str string, level func(msg string, fields ...zap.Fi
 
 // IsNeedCoolDownTransferLeader use cooldown time after transfer leader to avoid unnecessary schedule
 func (stat *HotPeerStat) IsNeedCoolDownTransferLeader(minHotDegree int) bool {
-	return time.Since(stat.lastTransferLeaderTime).Seconds() < float64(minHotDegree*RegionHeartBeatReportInterval)
+	return time.Since(stat.lastTransferLeaderTime).Seconds() < float64(minHotDegree*HotStatReportInterval)
 }
 
 // IsNeedDelete to delete the item in cache.
diff --git a/server/statistics/hot_peer_cache.go b/server/statistics/hot_peer_cache.go
index b2755322f2a0..6bf25c5eab0d 100644
--- a/server/statistics/hot_peer_cache.go
+++ b/server/statistics/hot_peer_cache.go
@@ -31,8 +31,8 @@ const (
 	HotThresholdRatio = 0.8
 	// ReportInterval indicates the interval between each data reporting
 	// TODO: change into StoreHeartBeatReportInterval when we use store heartbeat to report data
-	ReportInterval = RegionHeartBeatReportInterval
-	topNTTL        = 3 * ReportInterval * time.Second
+	HotStatReportInterval = RegionHeartBeatReportInterval
+	topNTTL               = 3 * HotStatReportInterval * time.Second
 
 	rollingWindowsSize = 5
 
@@ -123,24 +123,18 @@ func (f *hotPeerCache) collectPeerMetrics(byteRate, keyRate float64, interval ui
 
 // CheckRegionFlow checks the flow information of region.
 func (f *hotPeerCache) CheckRegionFlow(region *core.RegionInfo) (ret []*HotPeerStat) {
-	regionID := region.GetID()
-	storeIDs := f.getAllStoreIDs(region)
-	var peers []uint64
-	for _, peer := range region.GetPeers() {
-		peers = append(peers, peer.StoreId)
-	}
-
 	reportInterval := region.GetInterval()
 	interval := reportInterval.GetEndTimestamp() - reportInterval.GetStartTimestamp()
-
 	{
+		// TODO: collect metrics by peer stat
 		bytes := float64(f.getRegionBytes(region))
 		keys := float64(f.getRegionKeys(region))
 		byteRate := bytes / float64(interval)
 		keyRate := keys / float64(interval)
 		f.collectRegionMetrics(byteRate, keyRate, interval)
 	}
-
+	regionID := region.GetID()
+	storeIDs := f.getAllStoreIDs(region)
 	for _, storeID := range storeIDs {
 		peer := region.GetStorePeer(storeID)
 		var item *HotPeerStat
@@ -152,15 +146,16 @@ func (f *hotPeerCache) CheckRegionFlow(region *core.RegionInfo) (ret []*HotPeerS
 				SetWriteBytes(region.GetBytesWritten())
 			item = f.CheckPeerFlow(peerInfo, region, interval)
 		} else {
-			// Not in region anymore
-			item = f.getOldHotPeerStat(regionID, storeID)
-			item.needDelete = true
+			item = f.markExpiredItem(regionID, storeID)
 		}
 		if item != nil {
 			ret = append(ret, item)
 		}
 	}
-
+	var peers []uint64
+	for _, peer := range region.GetPeers() {
+		peers = append(peers, peer.StoreId)
+	}
 	log.Debug("region heartbeat info",
 		zap.String("type", f.kind.String()),
 		zap.Uint64("region", region.GetID()),
@@ -355,7 +350,7 @@ func (f *hotPeerCache) isRegionHotWithPeer(region *core.RegionInfo, peer *metapb
 }
 
 func (f *hotPeerCache) getDefaultTimeMedian() *movingaverage.TimeMedian {
-	return movingaverage.NewTimeMedian(DefaultAotSize, rollingWindowsSize, RegionHeartBeatReportInterval*time.Second)
+	return movingaverage.NewTimeMedian(DefaultAotSize, rollingWindowsSize, HotStatReportInterval*time.Second)
 }
 
 func (f *hotPeerCache) updateHotPeerStat(newItem, oldItem *HotPeerStat, bytes, keys float64, interval time.Duration) *HotPeerStat {
@@ -371,7 +366,7 @@ func (f *hotPeerCache) updateHotPeerStat(newItem, oldItem *HotPeerStat, bytes, k
 		if !isHot {
 			return nil
 		}
-		if interval.Seconds() >= RegionHeartBeatReportInterval {
+		if interval.Seconds() >= HotStatReportInterval {
 			newItem.HotDegree = 1
 			newItem.AntiCount = hotRegionAntiCount
 		}
@@ -389,6 +384,7 @@ func (f *hotPeerCache) updateHotPeerStat(newItem, oldItem *HotPeerStat, bytes, k
 	newItem.rollingByteRate = oldItem.rollingByteRate
 	newItem.rollingKeyRate = oldItem.rollingKeyRate
 
+	// TODO: don't inherit hot degree after transfer leader when we report peer by store heartbeat.
 	if newItem.justTransferLeader {
 		// skip the first heartbeat flow statistic after transfer leader, because its statistics are calculated by the last leader in this store and are inaccurate
 		// maintain anticount and hotdegree to avoid store threshold and hot peer are unstable.
@@ -453,6 +449,22 @@ func (f *hotPeerCache) getRegionKeys(region *core.RegionInfo) uint64 {
 	return 0
 }
 
+// TODO: remove it in future
+func (f *hotPeerCache) collectRegionMetrics(byteRate, keyRate float64, interval uint64) {
+	regionHeartbeatIntervalHist.Observe(float64(interval))
+	if interval == 0 {
+		return
+	}
+	if f.kind == ReadFlow {
+		readByteHist.Observe(byteRate)
+		readKeyHist.Observe(keyRate)
+	}
+	if f.kind == WriteFlow {
+		writeByteHist.Observe(byteRate)
+		writeKeyHist.Observe(keyRate)
+	}
+}
+
 // TODO: remove it in future
 // gets the storeIDs, including old region and new region
 func (f *hotPeerCache) getAllStoreIDs(region *core.RegionInfo) []uint64 {
@@ -482,18 +494,8 @@ func (f *hotPeerCache) getAllStoreIDs(region *core.RegionInfo) []uint64 {
 	return ret
 }
 
-// TODO: remove it in future
-func (f *hotPeerCache) collectRegionMetrics(byteRate, keyRate float64, interval uint64) {
-	regionHeartbeatIntervalHist.Observe(float64(interval))
-	if interval == 0 {
-		return
-	}
-	if f.kind == ReadFlow {
-		readByteHist.Observe(byteRate)
-		readKeyHist.Observe(keyRate)
-	}
-	if f.kind == WriteFlow {
-		writeByteHist.Observe(byteRate)
-		writeKeyHist.Observe(keyRate)
-	}
+func (f *hotPeerCache) markExpiredItem(regionID, storeID uint64) *HotPeerStat {
+	item := f.getOldHotPeerStat(regionID, storeID)
+	item.needDelete = true
+	return item
 }