diff --git a/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/TsFileProcessor.java b/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/TsFileProcessor.java
index 84b79c77a8f28160f6daf164a93f9bc8c4a5d26a..66e30355110f542947dab1f91a293edb09cda7ef 100644
--- a/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/TsFileProcessor.java
+++ b/server/src/main/java/org/apache/iotdb/db/engine/storagegroup/TsFileProcessor.java
@@ -1187,7 +1187,7 @@ public class TsFileProcessor {
               vmLogger.logFile(TARGET_NAME, newVmFile);
               // merge vm files
               logger.info("{}: {} merge level {} {} vms to vm", storageGroupName,
-                  tsFileResource.getTsFile().getName(), i, vmMergeTsFiles.size());
+                  tsFileResource.getTsFile().getName(), i, vmMergeTsFiles.get(i).size());
               // merge all vm files into a new vm file
               File tmpFile = createNewTmpFile();
               RestorableTsFileIOWriter tmpWriter = new RestorableTsFileIOWriter(tmpFile);