Aiming at the present situation that there still exists a large number of manual or semiautomatic way to sand blasting and rust removing of inner wall of pipeline, not only sand blasting efficiency is low, but also the working environment is unsafe, a kind of automatic sand blasting system for pipeline inner wall is developed based on Programmable Logical Controller (PLC) control. The sand blasting mechanism of pipeline was described, and the overall structure and function of the automatic sand blasting system, as well as its main work process were analyzed. With the pneumatic transmission as driving force and SIEMENS S7-200PLC as control core, a control technology combined electromechanical with electrical was proposed. On these bases, the hardware configuration and software programming of the control system were completed. The practice shows that the system has the characteristics of high blasting efficiency, small occupation area and high quality of rust removing.