Based on the Maxwell equation and simulation analysis method, this paper investigates and retains the optimized parameters of a high-speed solenoid valve, which is very important for electrical unit pump (EUP) diesels. According to the electromagnetic theory, firstly, a three-dimensional (3D) model of the solenoid valve is established, and working process of the electromagnets is analyzed by using both the theoretical method and Ansys Workbench software. In view of the electromagnetic force, furthermore, several parameters related to the solenoid valve performance are considered and their effects on solenoid valve are analyzed and discussed. Finally, the optimized parameters are proposed for the analyzed solenoid valve and proved by theoretical equations. The studied approach can be extended to any other field related to the electromagnetic device design.