For the special structure of the MR damper, the magnetic circuit structure of the damper is determined by static magnetic field simulation. The ANSYS software is used to simulate the transient magnetic field of the damper piston to obtain the electromagnetic response process of the damper under the step voltage. The influence of eddy current on the electromagnetic response process of the damper is obtained by comparison with the simplified mathematical model. The shear yield stress time-history curve of the magnetorheological fluid in the flow channel is obtained from the finite element simulation results of the magnetic field. The measured response time of the damping force is obtained by the damper dynamic response test experiment. The results show that the calculated shear yield stress time history curve is basically consistent with the measured response process of the damping force, indicating that the electromagnetic response is the main factor affecting the dynamic response of the MR damper.