Abstract: Traditional way of dicing potato seeds is accomplished mainly by manual work, which has low degree of automation.To solve this problem, a series of system for dicing potato seeds were designed.Based on Siemens S7-1200 PLC and MCGS configuration, the system will use the image processing capability of PC machine to analyze potato image collected by industrial camera and establish ellipsoidal model to get the weight of the potato and the position of the seed bud.Calculating the type of the cutter we need and the rotation of the cutter by the logical operation function of PLC, and using MCGS touch screen to carry on the real-time monitor to working process. This paper has achieved the design of potato seeds dicing machine control system by writing PLC control programs and designing operation interface of touch screen.After the debugging and application verification, the system can adapt the potato seeds dicing environment quite well and saved a lot of labor, besides, it also has a positive impact on the environment.