The PLC control system is one of the most common and most important operating system,which is related to the stability and security of the whole production.In order to ensure the normal operation of production activities,the normal operation of the PLC control system,the research on the possible interference factors in the operation of the system,which are mainly divided into external and internal two directions.In this paper,we will analyze the possible sources of interference from the PLC control system,and design a solution to the phenomenon of interference in different aspects.Starting with the design of hardware and software,the measures of anti interference are studied.Through the experimental analysis,the stability and anti disturbance degree of the PLC system after the anti interference measures are analyzed.The experimental results show that the PLC system can be improved to a large extent by the improved method.