diff --git a/com.creditease.uav.monitorframework/src/main/java/com/creditease/monitor/captureframework/spi/CaptureConstants.java b/com.creditease.uav.monitorframework/src/main/java/com/creditease/monitor/captureframework/spi/CaptureConstants.java
index d6f78125..51030169 100644
--- a/com.creditease.uav.monitorframework/src/main/java/com/creditease/monitor/captureframework/spi/CaptureConstants.java
+++ b/com.creditease.uav.monitorframework/src/main/java/com/creditease/monitor/captureframework/spi/CaptureConstants.java
@@ -25,8 +25,8 @@
  */
 public class CaptureConstants {
 
-    // 1 day ttl for tmax, tmin
-    public final static long MEI_INST_TTL = 24 * 3600 * 1000;
+    // 1 hour ttl for tmax, tmin
+    public final static long MEI_INST_TTL = 1 * 3600 * 1000;
 
     // default monitor id
     public final static String MONITOR_SERVER = "server";
diff --git a/com.creditease.uav.monitorframework/src/main/java/com/creditease/monitor/handlers/AbsServerRespTimeCapHandler.java b/com.creditease.uav.monitorframework/src/main/java/com/creditease/monitor/handlers/AbsServerRespTimeCapHandler.java
index b2c7b249..0964cd30 100644
--- a/com.creditease.uav.monitorframework/src/main/java/com/creditease/monitor/handlers/AbsServerRespTimeCapHandler.java
+++ b/com.creditease.uav.monitorframework/src/main/java/com/creditease/monitor/handlers/AbsServerRespTimeCapHandler.java
@@ -65,14 +65,14 @@ protected void recordCounters(CaptureContext context, MonitorElementInstance ins
             /**
              * NOTE: for no-http
              */
-            if (rtCode==-1) {
+            if (rtCode == -1) {
                 inst.increValue(CaptureConstants.MEI_ERROR);
-                respCode="Err";
+                respCode = "Err";
             }
-            else if (rtCode==1) {
-                respCode="OK";
+            else if (rtCode == 1) {
+                respCode = "OK";
             }
-            
+
             inst.increValue(CaptureConstants.MEI_RC + respCode);
         }
     }
@@ -103,14 +103,18 @@ protected void doCommonCounters(CaptureContext context, MonitorElementInstance i
                 MonitorElementInstance.CompareSetOperation.MAX);
 
         /**
-         * NOTE: tmax, tmin, 每24小时会自动RESET，避免一个巨大的tmax或一个很小的tmin
+         * NOTE: tmax, tmin, 每1小时会自动RESET，避免一个巨大的tmax或一个很小的tmin
          */
         if (isMax == true) {
 
             inst.setValue(CaptureConstants.MEI_RESP_MAXTIME_ST, end);
         }
         else {
-            long tmax_st = (Long) inst.getValue(CaptureConstants.MEI_RESP_MAXTIME_ST);
+            Object tmaxSt = inst.getValue(CaptureConstants.MEI_RESP_MAXTIME_ST);
+            if (tmaxSt == null) {
+                return;
+            }
+            long tmax_st = (Long) tmaxSt;
 
             if (end - tmax_st > CaptureConstants.MEI_INST_TTL) {
                 inst.setValue(CaptureConstants.MEI_RESP_MAXTIME, new AtomicLong(respTime));
@@ -126,9 +130,13 @@ protected void doCommonCounters(CaptureContext context, MonitorElementInstance i
             inst.setValue(CaptureConstants.MEI_RESP_MINTIME_ST, end);
         }
         else {
-            long tmax_st = (Long) inst.getValue(CaptureConstants.MEI_RESP_MINTIME_ST);
+            Object tminSt = inst.getValue(CaptureConstants.MEI_RESP_MINTIME_ST);
+            if (tminSt == null) {
+                return;
+            }
+            long tmin_st = (Long) tminSt;
 
-            if (end - tmax_st > CaptureConstants.MEI_INST_TTL) {
+            if (end - tmin_st > CaptureConstants.MEI_INST_TTL) {
                 inst.setValue(CaptureConstants.MEI_RESP_MINTIME, new AtomicLong(respTime));
                 inst.setValue(CaptureConstants.MEI_RESP_MINTIME_ST, end);
             }