The structural design of the shock absorber was analyzed according to the damping force theory mathematical model,and the magnetic circuit structure model was established based on finite element simulation to deeply analyze the influence of different magnetic circuit structures on the magnetic field distribution characteristics and dynamic response.The results show that a small damping gap is beneficial to increase the magnetic induction intensity and reduce the response time; the increase of the effective length of the piston can reduce the magnetic induction intensity while reducing the response time,the shape of the magnetic pole has little effect on the both.Considering the magnetic field distribution and response time,the reasonable structural parameter range of movable plug head was given,which provided reference for the structural design and optimization of MR damper.