diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/authority/AuthorityRuleManager.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/authority/AuthorityRuleManager.java
index 2c762282..eb7e889d 100755
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/authority/AuthorityRuleManager.java
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/authority/AuthorityRuleManager.java
@@ -124,7 +124,7 @@ public class AuthorityRuleManager {
             Map<String, List<AuthorityRule>> newRuleMap = new ConcurrentHashMap<String, List<AuthorityRule>>();
             for (AuthorityRule rule : list) {
                 if (StringUtil.isBlank(rule.getLimitApp())) {
-                    rule.setLimitApp(FlowRule.DEFAULT);
+                    rule.setLimitApp(FlowRule.LIMIT_APP_DEFAULT);
                 }
 
                 String identity = rule.getResource();
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/degrade/DegradeRuleManager.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/degrade/DegradeRuleManager.java
index fbc43fff..581b3116 100755
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/degrade/DegradeRuleManager.java
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/degrade/DegradeRuleManager.java
@@ -143,7 +143,7 @@ public class DegradeRuleManager {
 
             for (DegradeRule rule : list) {
                 if (StringUtil.isBlank(rule.getLimitApp())) {
-                    rule.setLimitApp(FlowRule.DEFAULT);
+                    rule.setLimitApp(FlowRule.LIMIT_APP_DEFAULT);
                 }
 
                 String identity = rule.getResource();
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRule.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRule.java
index 87977251..3d13fb3b 100755
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRule.java
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRule.java
@@ -40,20 +40,25 @@ import com.alibaba.csp.sentinel.slots.clusterbuilder.ClusterBuilderSlot;
  */
 public class FlowRule extends AbstractRule {
 
-    public static final String DEFAULT = "default";
-    public static final String OTHER = "other";
+    public static final String LIMIT_APP_DEFAULT = "default";
+    public static final String LIMIT_APP_OTHER = "other";
+
+    public FlowRule(){
+        super();
+        setLimitApp(LIMIT_APP_DEFAULT);
+    }
 
     /**
      * The threshold type of flow control (0: thread count, 1: QPS).
      */
-    private int grade;
+    private int grade = RuleConstant.FLOW_GRADE_QPS;
 
     private double count;
 
     /**
      * 0为直接限流;1为关联限流;2为链路限流
      */
-    private int strategy;
+    private int strategy = RuleConstant.STRATEGY_DIRECT;
 
     private String refResource;
 
@@ -181,7 +186,7 @@ public class FlowRule extends AbstractRule {
                 return node;
             }
 
-        } else if (limitApp.equals(DEFAULT)) {
+        } else if (LIMIT_APP_DEFAULT.equals(limitApp)) {
             if (strategy == RuleConstant.STRATEGY_DIRECT) {
                 return node.getClusterNode();
             }
@@ -201,7 +206,7 @@ public class FlowRule extends AbstractRule {
                 return node;
             }
 
-        } else if (limitApp.equals(OTHER) && FlowRuleManager.isOtherOrigin(origin, getResource())) {
+        } else if (LIMIT_APP_OTHER.equals(limitApp) && FlowRuleManager.isOtherOrigin(origin, getResource())) {
             if (strategy == RuleConstant.STRATEGY_DIRECT) {
                 return context.getOriginNode();
             }
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRuleComparator.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRuleComparator.java
index 2af7378a..b5d091c1 100755
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRuleComparator.java
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRuleComparator.java
@@ -30,9 +30,9 @@ public class FlowRuleComparator implements Comparator<FlowRule> {
             return 0;
         }
 
-        if (FlowRule.DEFAULT.equals(o1.getLimitApp())) {
+        if (FlowRule.LIMIT_APP_DEFAULT.equals(o1.getLimitApp())) {
             return 1;
-        } else if (FlowRule.DEFAULT.equals(o2.getLimitApp())) {
+        } else if (FlowRule.LIMIT_APP_DEFAULT.equals(o2.getLimitApp())) {
             return -1;
         } else {
             return 0;
diff --git a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRuleManager.java b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRuleManager.java
index b734fa91..decc6c2e 100755
--- a/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRuleManager.java
+++ b/sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRuleManager.java
@@ -111,7 +111,7 @@ public class FlowRuleManager {
 
         for (FlowRule rule : list) {
             if (StringUtil.isBlank(rule.getLimitApp())) {
-                rule.setLimitApp(FlowRule.DEFAULT);
+                rule.setLimitApp(FlowRule.LIMIT_APP_DEFAULT);
             }
 
             Controller rater = new DefaultController(rule.getCount(), rule.getGrade());