Abstract: With the purpose of upgrading automation control level, a process control system has been developed for the new five-stand tandem cold mill in Tangsteel, using the PC server and Windows 2000 operation system as the system platform. Database, human-machine interface (HMI) and core control system are all included in the design of the process control system, where the Oracle database is used to store all the data needed to save or exchange and the HMI is developed with VB language to implement the man-machine interaction. Based on the VAIronment software development environment, the core control system is developed with C++ language to implement such auxiliary functions as system management, data communication, running message management, tag message management and process tracking, with the core set values computed through computation module. The application result in site shows that the system can provide accurate setting values.