Accurate and fast solution of the electromagnetic characteristics problems is of great significance for the study of dynamic characteristics and reliability design of electromagnetic railguns. Based on the COMSOL moving mesh function, a new form of meshing—slip mesh combined with moving mesh—is proposed. The armature area and the track part where the pivot rail is in contact are meshed in to slip mesh, and the rest of the track part is dynamically meshed. This division method can not only solve the problems of low computational accuracy (coarse mesh) and high computational complexity (fine mesh) of “static mesh”, but also accurately solve the dynamic electromagnetic characteristics problems of transient and fast-moving models. The pulsed excitation current was used to simulate and analyze the established electromagnetic railgun model. The computing time and number of computational units of the three static meshes are compared with the meshing method proposed in this paper. The simulation results of different meshing methods on the armature motion velocity and the current density distribution at the armature center position are compared, and it is proved that the proposed meshing method is effective and efficient.