Abstract: This paper conducted a study on the effects of polymerization condition, composition and chlorination degree of chlorinated polyethylene (CPE) rubber on the grafting rate of chlorinated polyethylene grafted with acrylonitrile and styrene (ACS resin) synthesized by high-temperature bulk polymerization. The results indicated that the grafting reaction mainly took place in the early stage at which the conversion was low than 50 %. The grafting rate of ACS resin was significantly affected by polymerization temperature and the content of initiator and chain transfer agent. The improvement of polymerization temperature or the content of initiator and chain transfer agent resulted in a significant decrease in grafting rate. However, the weight ratio of styrene/acrylonitrile, the content and chlorination degree of CPE showed fewer effects.