In order to improve the performance of the shock absorber of aircraft landing gear and study the application of magnetorheological damping technology in the shock absorption structure of aircraft landing gear, the structure and the working principle of a kind of magnetorheological damper with oil needle is proposed and the structure is designed. The optimization of the magnetic circuit is conducted and finally the damping force characteristic and damping effect have been studied through the vibration test and drop test. The results show that the damping characteristic of the shock absorber is good and it has relative large adjustment range for the damping force and good energy dissipation performance. It could change the maximum vertical shock load and the piston displacement of different heights by changing the current.