OBJECTIVE：To provide reference for perfecting regional cooperation supervision mechanism under the marketing authorization holder （MAH） system in China. METHODS ：Based on the analysis of legal responsibilities of the MAH and entrusted manufacturing enterprise ，the problems were studied and suggestions for improving the regional cooperative supervision mechanism were put forward. RESULTS & CONCLUSIONS ：Sub-contract production is the main target of cross-regional collaborative supervision of drug regulatory agencies. The MAH is responsible for the entire life cycle of the drug ，and the entrusted manufacturing enterprise assumes supplementary responsibility. At present ， the problems of regional cooperation supervision are lacking of targeted legal enforcement basis ，insufficient supervision power ，difficulty in obtaining evidence ， untimely supervision and inadequate department cooperation supervision mechanism. It is necessary to improve the regional cooperative supervision mechanism continuously in perspectives of perfecting legislation ，establishing professional inspector system，improving departmental linkage mechanism ，and strenghtening the database construction.