In order to solve the problems of low operating efficiency and poor soil cultivation effect of potato cultivators in sandy loam soil conditions, a type of plowshare potato cultivator was designed. The overall structure and working principle of the machine were described. It clarified the main view of the plow body’s contour, the establishment of the guide curve, and the change law of the angle between the horizontal element straight line and the x-axis, and using the horizontal element line method, combined with the requirements of potato field tillage operation and dynamic analysis, the plow body structure parameters and their ranges that affected the effect of soil plow operation were determined. Based on the EDEM discrete element simulation technology, a component-soil simulation model was established. The soil height and soil fragmentation rate were used as test indicators. The tangent angle at the upper end of the guide curve, the initial element line angle, and the element line angle difference were the test factors, and the simulated quadratic orthogonal rotation regression test was carried out. Field experiments were conducted on the basis of simulation. The test results showed that the plowshare potato field cultivator developed had the soil crushing rate of 94.7%, the soil height of 8.4cm, the working depth was 13.6cm, the root depth stability coefficient was 92.1%, and the fuel consumption was 14.6kg/hm2, which was significantly better than the shovel type potato field cultivator’s operating efficiency and results, and satisfied the operating requirements of the potato field cultivator.