In order to simulate the aircraft ground motion realistic enough, this paper presents a landing gear dynamics model with high effectiveness and fidelity. The structure and force loading of the landing gear were not simplified while modeling. To obtain all forces and moments of landing gear relative to aircraft, the model considered wheel contact point, absorber compression stroke and velocity, absorber force and ground friction of each landing gear. By integrating those forces with aerodynamics and effects from engine, the model could simulate ground motion of aircraft under any conditions. Simulation results show that the present model can realize all basic functions of landing gear (drop, turn, brake, etc.), which makes it reflect the ground motion characteristics of aircraft effectively. This model can provide realistic takeoff/landing sensation for pilot, if it is loaded to simulator with motion platform.