diff --git a/flink-cdc-composer/src/main/java/org/apache/flink/cdc/composer/flink/translator/DataSinkTranslator.java b/flink-cdc-composer/src/main/java/org/apache/flink/cdc/composer/flink/translator/DataSinkTranslator.java
index efbdb8686ff..72355d5e70c 100644
--- a/flink-cdc-composer/src/main/java/org/apache/flink/cdc/composer/flink/translator/DataSinkTranslator.java
+++ b/flink-cdc-composer/src/main/java/org/apache/flink/cdc/composer/flink/translator/DataSinkTranslator.java
@@ -20,6 +20,8 @@
 import org.apache.flink.api.common.typeinfo.TypeInformation;
 import org.apache.flink.api.connector.sink2.Sink;
 import org.apache.flink.api.connector.sink2.TwoPhaseCommittingSink;
+import org.apache.flink.api.connector.source.Boundedness;
+import org.apache.flink.api.dag.Transformation;
 import org.apache.flink.cdc.common.annotation.Internal;
 import org.apache.flink.cdc.common.annotation.VisibleForTesting;
 import org.apache.flink.cdc.common.configuration.Configuration;
@@ -48,6 +50,8 @@
 import org.apache.flink.streaming.api.operators.OneInputStreamOperatorFactory;
 import org.apache.flink.streaming.api.transformations.LegacySinkTransformation;
 import org.apache.flink.streaming.api.transformations.PhysicalTransformation;
+import org.apache.flink.streaming.api.transformations.WithBoundedness;
+import org.apache.flink.util.Preconditions;
 
 import java.lang.reflect.InvocationTargetException;
 
@@ -158,8 +162,9 @@ private <CommT> void addCommittingTopology(
                     ((WithPreCommitTopology<Event, CommT>) sink).addPreCommitTopology(written);
         }
 
-        // TODO: Hard coding stream mode and checkpoint
-        boolean isBatchMode = false;
+        boolean isBatchMode = !existsUnboundedSource(inputStream.getTransformation());
+
+        // TODO: Hard coding checkpoint
         boolean isCheckpointingEnabled = true;
         DataStream<CommittableMessage<CommT>> committed =
                 preCommitted.transform(
@@ -209,4 +214,16 @@ private static <CommT> SimpleVersionedSerializer<CommT> getCommittableSerializer
             throw new RuntimeException("Failed to create CommitterOperatorFactory", e);
         }
     }
+
+    private boolean existsUnboundedSource(final Transformation<?> transformation) {
+        return isUnboundedSource(transformation)
+                || transformation.getTransitivePredecessors().stream()
+                        .anyMatch(this::isUnboundedSource);
+    }
+
+    private boolean isUnboundedSource(final Transformation<?> transformation) {
+        Preconditions.checkNotNull(transformation);
+        return transformation instanceof WithBoundedness
+                && ((WithBoundedness) transformation).getBoundedness() != Boundedness.BOUNDED;
+    }
 }