This paper adopts the adhere to the principle of legality in the retroactivity of the principle of application of the old law with the exception of a less punishment in the new law, according to the different behavior characteristics further distinction. 本文采用坚持罪刑法定原则在溯及力问题上的从旧兼从轻原则为主,再针对不同行为特征进一步区别对待。