Aiming at the problem of occurrence mechanism and application research of ship shaft frequency electric field signal source, a model of ship shaft frequency current based on equivalent circuit is established,using the laboratory axial current simulation device as the platform. The large shaft vibration of shaft current simulator is studied. Modeling and simulation of large shaft current is carried out. The large shaft current waveform diagram and its frequency spectrum at different rotational speeds are obtained. The shaft current experiment is carried out using the shaft current simulator. Comparing the simulation results with the experimental data of shaft current, the average error of the modeling method is within 8%. The feasibility of the modeling method verified to be feasible theoretically.