The rapid development of modern industry, continue to promote the automation and control technology and equipment innovation and the development of communications technology. Current, PLC, DCS, intelligent instruments, such has been widely applied to the field of production control system and the development of mutual collaboration by the device, common for distributed industrial control systems throughout the production process. In this system, fieldbus communications technology is essential. In this paper, a water station distributed control system project, introduced Shanghai Si Bo automated transfer Profibus-DP Modbus protocol gateway device application