In order to study landing gear retraction performance, research on an aircraft′s landing gear retraction system was carried out that combines a simulation and laboratory test. The working principle of the system was analyzed, and the dynamic mathematics model were derived in detail. A simulation model was established that combines the landing gear dynamics with the hydraulic system, and a laboratory test was carried out to verify the accuracy of the simulation model. Then, the damping characteristic of the hydraulic system were analyzed based on the simulation model and the test. The results show that the pressure curves of the co-simulation model agree with the test data, which verifies the accuracy of the co-simulation model. Moreover, both the simulation and test show that narrowing the damping hole makes the pressure change slowly and oscillate violently, leading to an obvious lagging stroke.