diff --git a/dftt_timecode/core.py b/dftt_timecode/core.py
index f7d8475..9b18054 100644
--- a/dftt_timecode/core.py
+++ b/dftt_timecode/core.py
@@ -87,7 +87,7 @@ def _(self, timecode_value, timecode_type='auto', fps=24.0, drop_frame=False, st
                 frame_index = ff + self.__nominal_fps * (ss + mm * 60 + hh * 3600)
             else:
                 drop_per_min = self.__nominal_fps / 30 * 2
-                if mm % 10 != 0 and ff in (0, drop_per_min - 1):  # 检查是否有DF下不合法的帧号
+                if mm % 10 != 0 and ss == 0 and ff in (0, drop_per_min - 1):  # 检查是否有DF下不合法的帧号
                     logging.log(40,
                                 'Timecode.__init__.smpte: This timecode is illegal under given params, check your input!')
                     raise DFTTTimecodeValueError