Abstract: The storage and transportation of crop straw is one of the main links in agricultural production. How to increase the straw bundling density and improve the space utilization rate of straw is a problem worth studying. Based on the analysis of the research status and progress of the circular baling machine, a monitoring system based on Siemens PLC was designed, and the hardware and software design of the control system were introduced in detail, which provided technical support for improving the operation performance of the baling machine.