In order to improve the efficiency and guarantee the quality of the research of cross-regional multi-center clinical trials, with the combination of WIN 2003 Server IIS, SQL Server 2005 database and ASP.Net programming techniques, the Pocock and Simon minimized randomization system model facing the network was put forward, and this system based on that model was developed. The two sides in this system can achieve cooperation process from screening subjects, random allocation and drug management to filling electronic case report form. Moreover, the customers of this system can also publish official documents, exchange information and take full use of other available assistant functions through the office automation platform.