In order to improve the dynamic response performance, reduce power consumption, and increase thrust consistency within stroke, the effects of key dimensions on the magnetic flux density and thrust force for both axial and radial magnetized voice coil motors (VCMs) are analyzed with the aid of finite element method. According to the simulation results, the optimal designs of the two types can be obtained pertinently, which ensures the rationality and accelerates the development cycles. By comparing the dynamic response, heating, and efficiency, it is concluded that the radial magnetized structure exhibits better performances under the specified requirements. On this basis, the magnetic field characteristics and static thrust force of the prototype are measured, verifying the reliability and feasibility of the finite element method. The proposed optimization idea can provide some reference for the future VCM design.