Aiming at the problem of lack of accurate and reliable discrete element simulation parameters for the research on the interaction mechanism of soil-rotary tillage components with sloping soil on the Loess Plateau and the optimized design of special rotary tillage equipment, taking the typical slope clay loam soil with common moisture content of 13.4%±1% on the Loess Plateau as the research object, the relevant parameters were calibrated based on Hertz-Mindlin with JKR Cohesion contact model in EDEM. Firstly, the contact parameters between soil particles were calibrated. The simulated accumulation angle of soil particles was used as the response value, the regression model of soil accumulation angle was obtained based on the Box-Behnken optimization method in the Design-Expert software. The regression model was optimized by using the measured accumulation angle as the target, and the optimization results of restitution coefficient, static friction coefficient, rolling friction coefficient and surface energy parameters between soil particles were 0.15, 0.33, 0.05 and 9.04J/m2, respectively. Under the optimal parameter combination, the simulation value of soil accumulation angle was 41.59°, and the relative error with the measured value was 3.8%. Then, the contact parameters between soil and rotary tillage knife material 65Mn steel were calibrated. The numerical range of the above three parameters between soil and 65Mn steel was obtained by static friction test, oblique plate test and impact test. Based on this, the static sliding friction angle of soil on 65Mn steel was obtained based on Box-Behnken optimization method. The regression model was optimized by using the measured static sliding friction angle as the target, and the optimization results of static friction coefficient, rolling friction coefficient and restitution coefficient between soil particles and 65Mn steel were 0.50, 0.06 and 0.18, respectively. Under the optimal parameter combination, the simulation value of static sliding friction angle was 24.0°, and the relative error with the measured value was 1.7%. Finally, through the comparative analysis of field test and simulation test of slope rotary tillage, it was concluded that the maximum relative errors of horizontal and lateral displacement of soil particles were 4.3% and 5.1% respectively, within the acceptable range. It showed that the calibration results and research methods of discrete element simulation parameters were accurate and reliable.