Abstract: Clock genes is prevalent in biological world， and they can bring and control biological circadian rhythm. There are new researches report that clock system not only work in biological circadian rhythm， but also in the regulation of other biologic function. If this system is destroyed， a series of diseases will occur， such as lymphoma， leucocythemia， breast cancer， depression and so on. This article is a review about the relationship between an important circadian clock gene Per2 and the tumor proliferation and apoptosis， the anti-tumor mechanisms of Per2， and the recent research Situation of Per2 in the gynecologic oncology.

Key words: Clock gene, Per2, Tumor, Biological circadian rhythm