Presents the design process of a automatic cleaning in place system based on programmable controller, including the overall design of the system, electrical control system design, work processes and the man-machine interface design, etc. The system adopts Siemens S7-200 PLC, Profibus DP fieldbus, man-machine interface and other advanced technologies, with multiple technological processes. After the system is put into operation, it works stably, operates simply, and has a high degree of automation, which brings good economic benefits for the company.