diff --git a/fe/fe-core/src/main/java/org/apache/doris/planner/external/BackendPolicy.java b/fe/fe-core/src/main/java/org/apache/doris/planner/external/BackendPolicy.java
index cdc436a83a..a7a7ba8cc3 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/planner/external/BackendPolicy.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/planner/external/BackendPolicy.java
@@ -58,7 +58,7 @@ public class BackendPolicy {
                 .needLoadAvailable()
                 .addTags(tags)
                 .preferComputeNode()
-                .assignCandidateNum(Config.backend_num_for_federation)
+                .assignExpectBeNum(Config.backend_num_for_federation)
                 .build();
         backends.addAll(policy.getCandidateBackends(Env.getCurrentSystemInfo().getIdToBackend().values()));
         if (backends.isEmpty()) {
diff --git a/fe/fe-core/src/main/java/org/apache/doris/system/BeSelectionPolicy.java b/fe/fe-core/src/main/java/org/apache/doris/system/BeSelectionPolicy.java
index 6c95f6ecfb..acd38f14bd 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/system/BeSelectionPolicy.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/system/BeSelectionPolicy.java
@@ -47,7 +47,7 @@ public class BeSelectionPolicy {
     public boolean allowOnSameHost = false;
 
     public boolean preferComputeNode = false;
-    public int candidateNum = Integer.MAX_VALUE;
+    public int expectBeNum = 0;
 
     private BeSelectionPolicy() {
 
@@ -105,8 +105,8 @@ public class BeSelectionPolicy {
             return this;
         }
 
-        public Builder assignCandidateNum(int candidateNum) {
-            policy.candidateNum = candidateNum;
+        public Builder assignExpectBeNum(int expectBeNum) {
+            policy.expectBeNum = expectBeNum;
             return this;
         }
 
@@ -141,25 +141,21 @@ public class BeSelectionPolicy {
 
     public List<Backend> getCandidateBackends(ImmutableCollection<Backend> backends) {
         List<Backend> filterBackends = backends.stream().filter(this::isMatch).collect(Collectors.toList());
-        Collections.shuffle(filterBackends);
         List<Backend> candidates = new ArrayList<>();
         if (preferComputeNode) {
             int num = 0;
             // pick compute node first
             for (Backend backend : filterBackends) {
                 if (backend.isComputeNode()) {
-                    if (num >= candidateNum) {
-                        break;
-                    }
                     candidates.add(backend);
                     num++;
                 }
             }
             // fill with some mix node.
-            if (num < candidateNum) {
+            if (num < expectBeNum) {
                 for (Backend backend : filterBackends) {
                     if (backend.isMixNode()) {
-                        if (num >= candidateNum) {
+                        if (num >= expectBeNum) {
                             break;
                         }
                         candidates.add(backend);
@@ -170,7 +166,7 @@ public class BeSelectionPolicy {
         } else {
             candidates.addAll(filterBackends);
         }
-
+        Collections.shuffle(candidates);
         return candidates;
     }
 
diff --git a/fe/fe-core/src/test/java/org/apache/doris/system/SystemInfoServiceTest.java b/fe/fe-core/src/test/java/org/apache/doris/system/SystemInfoServiceTest.java
index 546449b79c..0afa019310 100644
--- a/fe/fe-core/src/test/java/org/apache/doris/system/SystemInfoServiceTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/system/SystemInfoServiceTest.java
@@ -239,11 +239,11 @@ public class SystemInfoServiceTest {
         Assert.assertEquals(1, infoService.selectBackendIdsByPolicy(policy02, 1).size());
 
         BeSelectionPolicy policy03 = new BeSelectionPolicy.Builder().addTags(Sets.newHashSet(taga))
-                .setStorageMedium(TStorageMedium.HDD).preferComputeNode().assignCandidateNum(0).build();
-        Assert.assertEquals(0, infoService.selectBackendIdsByPolicy(policy03, 1).size());
+                .setStorageMedium(TStorageMedium.HDD).preferComputeNode().assignExpectBeNum(0).build();
+        Assert.assertEquals(1, infoService.selectBackendIdsByPolicy(policy03, 1).size());
 
         BeSelectionPolicy policy04 = new BeSelectionPolicy.Builder().addTags(Sets.newHashSet(taga))
-                .setStorageMedium(TStorageMedium.HDD).preferComputeNode().assignCandidateNum(1).build();
+                .setStorageMedium(TStorageMedium.HDD).preferComputeNode().assignExpectBeNum(1).build();
         Assert.assertEquals(1, infoService.selectBackendIdsByPolicy(policy04, 1).size());
 
         // one compute node and two mix node
@@ -264,11 +264,11 @@ public class SystemInfoServiceTest {
         Assert.assertEquals(0, infoService.selectBackendIdsByPolicy(policy05, 3).size());
 
         BeSelectionPolicy policy06 = new BeSelectionPolicy.Builder().addTags(Sets.newHashSet(taga))
-                .setStorageMedium(TStorageMedium.HDD).preferComputeNode().assignCandidateNum(2).build();
+                .setStorageMedium(TStorageMedium.HDD).preferComputeNode().assignExpectBeNum(2).build();
         Assert.assertEquals(2, infoService.selectBackendIdsByPolicy(policy06, 2).size());
 
         BeSelectionPolicy policy07 = new BeSelectionPolicy.Builder().addTags(Sets.newHashSet(taga))
-                .setStorageMedium(TStorageMedium.HDD).preferComputeNode().assignCandidateNum(3).build();
+                .setStorageMedium(TStorageMedium.HDD).preferComputeNode().assignExpectBeNum(3).build();
         Assert.assertEquals(3, infoService.selectBackendIdsByPolicy(policy07, 3).size());
     }