Abstract: Aimed at the requirements of automatic grinding for the insulation layer of small caliber solid rocket's engine compartments, designed a PLC control system with normal grinding functions and breakpoint grinding functions was proposed by using Mitsubishi FX3U series PLC and Weinview touch screen.The PLC control system can automatically grind the insulation layer under normal grinding, and also can realize the breakpoint grinding function under the condition of system failures, emergency stop and electrical power off accidentally. This paper discusse the hardware components of the grinding machine and its control system in detail, and gives the grinding speed control strategy and grinding process control flow. The application results show that the insulation layer grinding machine has the advantages of simple operation, safe and reliable, multi-functions and the HMI interface is easy to operate and can solve the problems of uneven grinding and low production efficiency effectively caused by grinding artificially.