Abstract: In recent year’s semi-active dampers utilizing smart fluids like magneto-rheological (MR) fluid have attracted attention of the researchers. These devices have found varied applications like control of vibrations in seat suspension systems, rotary braking systems, prosthetics, seismic systems etc. The performance of MR damper depends on its magnetic and hydraulic circuit design. This paper deals with a design of MR damper for which mathematical model is developed. A finite element model is built to examine and investigate the 2- D axi-symmetric MR damper. Six different configurations of MR damper piston are simulated in order to investigate how the shape of the piston affects the maximum pressure drop that the damper can provide. The piston velocity and the input current to the coil are varied to evaluate the resulting change in magnetic flux density (B) and pressure drop(ΔP). The simulation results of the different configuration of damper piston show that the performance of single coil with filleted piston ends is better than that of other configurations for the same magnitude of input current and piston velocity.