The electromagnet actuator is an important unit of low-voltage electric apparatus and the corresponding design method is a hot research area. The goal of electromagnet design is to minimize the volume (weight) or cost under the condition of satisfying requirement. And this goal is a typical optimum design study. The traditional design method of electromagnet is based on magnetic circuit principle which can derive analytical expression of magnetic force, structure parameters and exciting current. Then the optimization algorithm can be easily applied to meet design requirement. Though magnetic circuit principle can’t calculate magnetic field accurately and the correctness of calculating results can’t be verified. With development of finite element method and computer performance, the magnetic force of electromagnet can be calculated accurately. Because CAE method will discretize magnetic field, it’s difficult to use optimization algorithm. In our study Ansoft-Maxwell software is applied to simulate parameterized electromagnet model. And the genetic algorithm of the software is used to optimize model design. Finally the optimized plan of electromagnet can satisfy requirement.