diff --git a/dbsync/src/main/java/com/taobao/tddl/dbsync/binlog/event/GtidLogEvent.java b/dbsync/src/main/java/com/taobao/tddl/dbsync/binlog/event/GtidLogEvent.java
index b645e954..5c2678b5 100644
--- a/dbsync/src/main/java/com/taobao/tddl/dbsync/binlog/event/GtidLogEvent.java
+++ b/dbsync/src/main/java/com/taobao/tddl/dbsync/binlog/event/GtidLogEvent.java
@@ -44,13 +44,14 @@ public class GtidLogEvent extends LogEvent {
         gno = buffer.getLong64();
 
         // support gtid lastCommitted and sequenceNumber
-        // 42 = 1+16+8+1+8+8
-        if (buffer.capacity() > 42 && buffer.getUint8() == LOGICAL_TIMESTAMP_TYPE_CODE) {
+        // fix bug #776
+        if (buffer.hasRemaining() && buffer.remaining() > 16 && buffer.getUint8() == LOGICAL_TIMESTAMP_TYPE_CODE) {
             lastCommitted = buffer.getLong64();
             sequenceNumber = buffer.getLong64();
         }
 
 
+
         // ignore gtid info read
         // sid.copy_from((uchar *)ptr_buffer);
         // ptr_buffer+= ENCODED_SID_LENGTH;