Magneto-rhelological(MR) dampers are devices that use rheological fluids to modify the mechanical properties of fluid absorber. The mechanical simplicity, high dynamic range, large force capacity, lower power requirements, robustness and safe manner of operation have made MR dampers attractive devices for semi-active real-time control in civil, aerospace and automotive applications. Landing gear is one of the most essential components of the aircraft, which plays an extreme important role in preventing the airframe from vibration and excessive impact forces, improving passenger comfortable characteristics and increasing aircraft flight safety. In this paper, the semi-active system used in landing gear damping controller design, simulation, and the vibration test-bed are discussed and researched. The MR dampers employed in landing gear system were designed, manufactured and characterized as available semi-active actuators. On the basis of a large number of experimental data, a mathematical model based on the Bouc-Wen hysteresis model was adopted to predict both the force-displacement behavior and the complex nonlinear force-velocity response of the MR dampers. Using the landing gear vibration test-bed, the vibration characteristic of passive absorber was compared with the vibration characteristic of semi-active control. It is indicated that compared with passive control, the MR damper based on semi-active control can obviously restrain the displacement and acceleration response of the structure, and takes an effective performance in MR fluid absorber vibration reduction system.