A PROFI-BUS based industrial robot control system is introduced from the viewpoint of both software and hardware. It is discussed about how to use PC technology and field-bus technology to design an open robot control system. The system adopts a three- layer structure, which is mainly configured with universal control devices, to realize a modular and universal design. A high-speed field-bus is designed for connecting servo system and IPC, to ensure real-time capability; another low-speed Field-bus is used to connect IPC and PLC, HMI, teaching panel and other devices for data exchange, while reducing the occupancy of system resources. The software system adopts the modular design with Windows NT and RTX, which fully exploits the powerful functions of Window NT system and meets the requirements of real-time system. This open structure greatly enhances the system's flexibility and openness.