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In order to reduce torsion and consumption in rotary tillage operation, a self-excited vibration rotary blade device was designed based on the national standard IT245 rotary blade, and its working principle was described. Through the analysis of motion force, the selection of large spring parameters and the design of waist hole of spring spindle were completed. Based on DEM-MBD technology, the simulation model of soil rotary tiller interaction was established, and the variation law of three-dimensional resistance and torque of national standard and self-excited vibration rotary tiller under five knife shaft speeds was analyzed. In the simulation test, the effect of drag reduction and torque reduction was not obvious at the low speed when the cutter shaft speed was 150r/min and 200r/min. When the rotating speed was 250r/min and 300r/min, the self-excited vibration rotary blade had better drag and torque reduction effect than the national standard rotary blade. The vertical resistance was reduced by 6.96% and 10.41%, respectively, and the average torque reduction rate was larger, which were 9.80% and 19.63%, respectively. When it reached 350r/min, the drag and torque reduction effect was reduced. By analyzing the average torque of two kinds of rotary tiller simulation and soil tank test, the correlation coefficients of the national standard and the average torque curve of self-excited vibration rotary tiller were obtained, which were 0.997 and 0.998, respectively, which basically verified the accuracy of DEM-MBD coupling simulation model. The frequency domain analysis of the vibration acceleration data in the Y-direction collected in the soil trough test showed that with the increase of the rotating speed of the cutter shaft, the amplitude of the Y-direction power spectral density generally showed an upward trend. When the rotating speed reached 300r/min, the excitation frequency reached near the natural frequency of the installation in the Y-direction. At this time, resonance occurred, and the amplitude of the Y-direction power spectral density reached the maximum value. At this time, the rotary tiller obtained the maximum energy. The torque reduction was the largest, and the effect of reducing torque and consumption was the best.