In order to study the relationship between the performance of the electromagnetic system of the circuit breaker operating mechanism and the current curve of the closing and closing coils, combined with the changes of the core motion state, resistance and electromagnetic force in each stage of the closing process of the operating mechanism, the theoretical analysis of the coil current curve at each stage Influencing factors. Aiming at the problem that the circuit breaker is difficult to simulate, the magnetic circuit method is used to establish the equivalent magnetic circuit model of the electromagnetic system and the dynamic mathematical model of the electromagnetic system. The influence of the electromagnetic system parameter variation and the fault condition on the coil current curve is simulated. The simulation results show that the electromagnetic system parameter changes and fault conditions will make corresponding changes in the coil current curve, which provides an important reference for the state evaluation of the circuit breaker operating mechanism.