According to the requirements of Unmanned Aerial Vehicle(UAV)ground dynamic analysis,a leaf spring landing gear dynamics model was proposed to accurately reflect the dynamic characteristics of leaf spring deformations.On the basis of modal analysis,the leaf spring landing data were obtained by using the finite element method through modifying stiffness matrix and the model was simplified by modal reduction.After dissolving decoupling vibration differential equations by modal coordinate transformation, a state space model was constructed to describe the dynamics of the leaf spring landing gear. Finally, statics, dynamics simulation tests as well as the leaf spring drop experiments were designed to validate the flexible model.These results demonstrate that the results from statespace model and from finite element software static analysis have only 0.07% error under static conditions.The deviation of drop simulation with this model from real drop experiment results is about 5% when its realtime simulation step is 1 ms,which satisfies the flight simulation requirements.