A mechanical performance testing device for planter openers based on PLC was designed. The testing device mainly included control mechanism of working depth, six component testing device, hydraulic system and PLC control system. In order to improve the stability of working depth, closed loop feedback was adopted for real time control. Six component method was used to measuring mechanical performance of opener. The results showed that the measurement precision and the maximum relative error about the traction resistance was 1.49% FS and 3.7%, the vertical counterforce was 2.1% FS and 5.1%, and the lateral force of modified was 0.98% FS and 1.9% with the calibration. The precision of testing device can meet requirements, and the performance testing device can test the force and working depth of different types of openers in high accuracy.