Aiming to further promotion the accuracy research on the process of the mechanized covering soil on whole plastic film mulching on double ridges. Combined with EDEM software, a discrete element simulation test was carried out on the covering soil friction angle (the repose angle of soil-soil and the sliding friction angle of soil-steel). Through the three-factor orthogonal combination test, the significant order of the contact parameters was obtained, which influenced the repose angle of soil-soil and the sliding friction angle of soil-steel. Based on the software regression analysis of Design-Expert 8.0.6 and response surface analysis method, the relationship between the influencing factors and evaluating indicator (repose angle and sliding friction angle) was established. The measured value of covering soil friction angle (the repose angle of soil-soil and the sliding friction angle of soil-steel) was selected as the chosen target;by using response surface method, the optimal aggregative index could be obtained under the condition that the static friction coefficient among soil was 0.68, the rolling friction coefficient among soil was 0.27, the restitution coefficient among soil was 0.21, the static friction coefficient of soil-steel was 0.31, the rolling friction coefficient of soil-steel was 0.13 and the restitution coefficient of soil-steel was 0.54. In order to verify the reliability of the contact parameters of discrete elements for covering soil on whole plastic film mulching on double ridges, the comparative analysis was made between the simulated test and the actual test of soil friction angle (the repose angle of soil-soil and the sliding friction angle of soil-steel), and the relative errors were 2.6% and 3.1%, respectively. The discrete element method was applied to simulate operation process of the device with covering soil on plastic-film seedbed under the condition of using the optimal contact parameters. The simulation result was consistent with the field test effect. Meanwhile, the parameters calibration method and regression model was feasible, which could provide references for the parameter setting of the soil discrete element simulation of farmland in the northwest arid area of China.