diff --git a/leveldb/db.go b/leveldb/db.go
index c348ed4..0fa0462 100644
--- a/leveldb/db.go
+++ b/leveldb/db.go
@@ -134,19 +134,18 @@ func (db *DB) NewWriteBatch() *WriteBatch {
 	return wb
 }
 
-//like c++ iterator, [begin, end)
-//begin should less than end
+//[begin, end]  close(inclusive) interval
 //if begin is nil, we will seek to first
-//if end is nil, we will next until read last
+//if end is nil, we will seek to last
 //limit <= 0, no limit
 func (db *DB) Iterator(begin []byte, end []byte, limit int) *Iterator {
 	return newIterator(db, db.iteratorOpts, begin, end, limit, forward)
 }
 
-//like c++ reverse_iterator, [rbegin, rend)
+//[rbegin, rend] close(inclusive) interval
 //rbegin should bigger than rend
 //if rbegin is nil, we will seek to last
-//if end is nil, we will next until read first
+//if end is nil, we will seek to first
 //limit <= 0, no limit
 func (db *DB) ReverseIterator(rbegin []byte, rend []byte, limit int) *Iterator {
 	return newIterator(db, db.iteratorOpts, rbegin, rend, limit, backward)
diff --git a/leveldb/iterator.go b/leveldb/iterator.go
index e8f1e19..7cbc213 100644
--- a/leveldb/iterator.go
+++ b/leveldb/iterator.go
@@ -62,11 +62,11 @@ func (it *Iterator) Valid() bool {
 	}
 
 	if it.direction == forward {
-		if it.stop != nil && bytes.Compare(it.Key(), it.stop) >= 0 {
+		if it.stop != nil && bytes.Compare(it.Key(), it.stop) > 0 {
 			return false
 		}
 	} else {
-		if it.stop != nil && bytes.Compare(it.Key(), it.stop) <= 0 {
+		if it.stop != nil && bytes.Compare(it.Key(), it.stop) < 0 {
 			return false
 		}
 	}
diff --git a/leveldb/leveldb_test.go b/leveldb/leveldb_test.go
index 6b9934b..6bee93c 100644
--- a/leveldb/leveldb_test.go
+++ b/leveldb/leveldb_test.go
@@ -176,7 +176,7 @@ func TestIterator(t *testing.T) {
 	}
 	it.Close()
 
-	if step != 5 {
+	if step != 6 {
 		t.Fatal("invalid step", step)
 	}
 
@@ -245,7 +245,7 @@ func TestIterator(t *testing.T) {
 	}
 	it.Close()
 
-	if step != 2 {
+	if step != 1 {
 		t.Fatal("invalid step", step)
 	}