The PROTAC (PROteolysis TArgeting Chimera) technology is a target protein degradation strategy, based on the ubiquitin-proteasome system, which has been gradually developed into a potential means of targeted cancer therapy in recent years. This strategy has already shown significant advantages over traditional small-molecule inhibitors in terms of pharmacodynamics, selectivity, and drug resistance. Several small molecule PROTACs have been in Phase I clinical trial. Herein, we have introduced the mechanism, characteristics, and advantages of PROTAC strategy. And we have summarized the recent advances in the development of small-molecule PROTACs for cancer treatment. We hope this review will be helpful in optimizing the design of the ideal small- molecule PROTACs and advancing targeted anticancer research.