This paper introduces the principle of CIP technology and the research status of CIP cleaning system at home and abroad. And from the practical application, this paper introduces the application of S7-200PLC, touch screen technology and related software in the online cleaning system. And using MPI communication protocol improves the degree of automation and reliability of the equipment. By setting the different operation parameters to ensure the normal operation of the CIP cleaning system, the control system is no longer simplification. Increase the control system of feedback loop, making the system in a confined space, to ensure the safety of operation. The results show that the system is reliable and stable, the operation is simple, and the design requirements are achieved.