In order to solve the problem of soil disturbance caused by straw returning interval deep sowing combined operation machine in conservation tillage, an interval subsoiler with direct injection deep sowing shovel was designed. The discrete element simulation and field experiment method were used to study the different shovel body width affect the behavior of soil disturbance. Taking tillage specific resistance, soil swelling degree and soil disturbance coefficient as experimental indexes, the soil movement state and micro-movement in all directions under different shovel width conditions were compared, and the soil disturbance effect of direct injection deep loose shovel was analyzed. The results showed that tillage resistance was the minimum when the width of shovel was 350mm, and tillage specific resistance was the minimum when the width of shovel was 450mm. Soil disturbance was increased with the increase of shovel width, and the shovel width mainly affected soil lateral disturbance, soil retreat and ridge height. Reducing the width appropriately was beneficial to reduce soil lateral disturbance, increase soil retreat and reduce ridge height. The width of the shovel had an important effect on soil fluffiness and soil disturbance coefficient. When the width of the shovel was 350mm, the soil fluffiness was relatively small and the soil disturbance coefficient was relatively large. Different shovel width had certain influence on tillage resistance and disturbed area, and the influence degree of shovel width on disturbed area was greater than that of tillage resistance. Within the design parameters of shovel width, the average errors of test and simulation results of soil bulk degree and disturbance coefficient were 6.36% and 6.84%, respectively. The average errors of test and simulation values of tillage resistance and specific resistance were 9.02% and 12.41%, respectively. The effect of interval subsoiling machine on reducing soil disturbance was obvious, which can provide reference for the optimal design of subsoiling machine.