In the light of lower qualification rate of sowing depth and poorer quality of film edge covered with soil that the traditional potato combine seeders had, and according to characteristics of mechanized covering soil in the northwest dry farming areas and requirements of potato planting with mulching in Hexi Corridor, potato combined seeder machine with imitated terrain which had the integration of rotary tillage, sowing profiling ability of fertilizing, ridging, seeding, mulching and film edge covered soil was designed. To reduce impact on seeding depth in the process of wheel walking, using linkage principle the position of opener installed in the rack was calculated. In virtue of EDEM software parameters of chain structure were optimized with the simulation experiment of two factors and three levels, and the maximum diameter of chain was 77mm, and depth of one was 25.5mm. The amount of soil covered was calculated by relative motion to improve the quality of covering amount of soil. The height of the back end of the shovel was 70mm, and the velocity of the rotation angle of the blade was 4rad/s, the radius of the impeller was 230mm, increasing the breaking soil performance of the impeller. Test results showed that when the operation speed of overall unit was 0.69m/s, qualified index of throwing and covering soil on film edge was 88.6%, missed index was 5.3%, replay index was 6.1%, the planting depth qualified rate was 90.4%, seed spacing qualified index was 89.4%, which met the agricultural industry standard requirement. Angle between inter film soil and ground was 65.3°, which met the requirement of potato planting and mulching in the western corridor of Gansu.