diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/commands/ExportCommand.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/commands/ExportCommand.java
index a48753a119..2be6e84938 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/commands/ExportCommand.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/commands/ExportCommand.java
@@ -304,11 +304,11 @@ public class ExportCommand extends Command implements ForwardWithSync {
         exportJob.setQualifiedUser(ctx.getQualifiedUser());
         exportJob.setUserIdentity(ctx.getCurrentUserIdentity());
 
-        Optional<SessionVariable> optionalSessionVariable = Optional.ofNullable(
-                ConnectContext.get().getSessionVariable());
-        exportJob.setSessionVariables(optionalSessionVariable.orElse(VariableMgr.getDefaultSessionVariable()));
-        exportJob.setTimeoutSecond(optionalSessionVariable.orElse(VariableMgr.getDefaultSessionVariable())
-                .getQueryTimeoutS());
+        // Must copy session variable, because session variable may be changed during export job running.
+        SessionVariable clonedSessionVariable = VariableMgr.cloneSessionVariable(Optional.ofNullable(
+                ConnectContext.get().getSessionVariable()).orElse(VariableMgr.getDefaultSessionVariable()));
+        exportJob.setSessionVariables(clonedSessionVariable);
+        exportJob.setTimeoutSecond(clonedSessionVariable.getQueryTimeoutS());
 
         // exportJob generate outfile sql
         exportJob.generateOutfileLogicalPlans(RelationUtil.getQualifierName(ctx, this.nameParts));
diff --git a/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java b/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java
index 1d1edbb213..14afc7a1bc 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java
@@ -245,12 +245,16 @@ public class VariableMgr {
     public static SessionVariable newSessionVariable() {
         wlock.lock();
         try {
-            return (SessionVariable) SerializationUtils.clone(defaultSessionVariable);
+            return cloneSessionVariable(defaultSessionVariable);
         } finally {
             wlock.unlock();
         }
     }
 
+    public static SessionVariable cloneSessionVariable(SessionVariable var) {
+        return SerializationUtils.clone(var);
+    }
+
     // Check if this setVar can be set correctly
     // Do not use ErrorReport.reportDdlException to throw exeception, it will set the query state in connection context.
     // But in some case, we do not want to set the query state and need to ignore that error.