Abstract: In order to solve the problem of big resistance in digging potatoes, the virtual design of digging blade was made by using Inventor, a parameter feature modeling software, and the draught resistance mathematic model was set up based on dynamics analysis of digging blade and soil. Simulation tests between the resistance and the main factors, such as working velocity, obliquity of blade, digging depth, digging breadth, were done by visual basic on Computer Aided Analysis(CAA), the design parameters of digging blade were confirmed and put into the virtual model to redesign the digging blade, at last the digging blade was manufactured, the draught resistance tests in the soil groove and the harvesting tests in the field were carried out. The draught resistances were consistent basically between the simulation tests and the soil groove tests, which showed that the CAA program and the simulation tests were effective and feasible. The field harvesting test results show that the harvest quality is better, these results also prove that the digging blade parameters are reasonable. This method, through CAA, simulation tests, and virtual design, may provide a reference for other agricultural machine design.