To reduce tire loads, increase landing performance and develop method of metering pin, it is presented that Landing Gear theoretical model based on planar dynamics of multibody systems. And then two-object optimization design of landing gear performance is performed using NSGA-II Genetic Algorithm, whose design varialbes are cross-section diameters at different axial positions of metering pin and whose objective functions are shock-absorbing efficiency and overload factor. Results show that shock-absorbing efficiency has been increased, overload factor reduced, and load environment of tires and landing performance improved. Approach mentioned above is very effetive to design a best metering pin of a certain absorber.