diff --git a/flink-doris-connector/src/main/java/org/apache/doris/flink/tools/cdc/mongodb/MongoDBDatabaseSync.java b/flink-doris-connector/src/main/java/org/apache/doris/flink/tools/cdc/mongodb/MongoDBDatabaseSync.java
index eac6acc48..79c261d0c 100644
--- a/flink-doris-connector/src/main/java/org/apache/doris/flink/tools/cdc/mongodb/MongoDBDatabaseSync.java
+++ b/flink-doris-connector/src/main/java/org/apache/doris/flink/tools/cdc/mongodb/MongoDBDatabaseSync.java
@@ -114,7 +114,7 @@ public List<SourceSchema> getSchemaList() throws Exception {
                     throw new IllegalStateException("No documents in collection to infer schema");
                 }
 
-                long totalDocuments = collection.countDocuments();
+                long totalDocuments = collection.estimatedDocumentCount();
                 long sampleSize = (long) Math.ceil(totalDocuments * samplePercent);
                 ArrayList<Document> documents = sampleData(collection, sampleSize);
                 MongoDBSchema mongoDBSchema =