Aiming at simulating the hurdle-hop of tilt-rotor aircraft in forward flight near the ground, two models of numerical simulation and analysis based on optimal control theory were proposed. Firstly, Longitudinal flight dynamic model for tilt-rotor was modified considering the influence of ground effect. Secondly, the first model is combined with predicted trajectory from inverse simulation method, the inverse model of hurdle-hop of tilt-rotor is established based on optimal trajectory, and the

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... cond model is the optimal control model of unpredicted trajectory, which is formulated from the reasonable function of objective, path and boundary constraints for hurdle-hop with detailed analysis, solved two models by direct multiple shooting method and nonlinear programming algorithm. Finally, XV-15 as the sample vehicle. Two models for hurdle-hop based on optimal control theory was calculated, the history of optimal flight trajectory and control are given.