Magnetic circuit structure is the key point in the design of the magnetorheological fluid (MRF) damper, which directly impacts the performance of the damper.By using the method of parametric simulation, the influence of the key structure parameters on the magnetic induction intensity of the gapmagnetic circuit is analyzed.Aiming at the design objective, the design variables were selected and the simulation model of the magnetic circuit was established.In the structural design of magnetic circuit of the MR damper, finite-element analysis(FEA) was introduced, and the parametric programming language was used to optimize the structural parameters of model.A prototype of MR damper was fabricated to verify the effect of optimization by experiments.Both simulation analyses and experiments show that the magnetic flux density at the gap has been significantly improved to meet the design goals, and the magnetic field distribution is more reasonable, after using the parametric programming language to optimize the magnetic circuit structure of the MR damper. So this is an effective method for the optimization design of magnetic circuit of the MR damper.