In view of the basic flow and control requirements of the acetaldehyde reaction process,the reactor temperature control and pressure control methods were studied, and the acetaldehyde reaction process control system based on Siemens S7-300 PLC was designed.Using WinCC configuration software to design the man-machine interface screen, realize the centralized monitoring and automatic control of the acetaldehyde reaction process,effectively improve the production efficiency of acetaldehyde ,and reduce the production labor force.