Abstract: The general method of dynamic equilibrium analysis is to decompose the unbalance mass into two selected parallel planes. Based on SolidWorks secondary development, this paper designs a human-computer interaction interface, which can calculate the dynamic balance of any screw rotor. Dynamic balance can be achieved by adding or removing the corresponding mass at the unbalance phase Angle position of the selected two planes to eliminate the unbalance on each surface. This reduces effort and improves design quality. The interface can be used to calculate the dynamic balance of any part.