Laser marking control system based on STM32 microcontroller was designed. Through analyzing the geometric distortion of laser marking system,a simplified correction method was presented. To control the laser marking process,the microcontroller was used to simulate the XY2-100 transmission and control protocol,which can control galvanometer scan and laser switch. A SDRAM and a NAND Flash are used to enhance the data processing capability of the microcontroller,and offline marking function is achieved. Based on polynomial fitting,a simple and effective formula to correct barrel distortion and pincushion distortion is proposed. Using this method,this laser marking system can meet the actual marking requirements.