Abstract: The fast autonomous landing of rotorcraft on a moving platform can improve the adaptability and flexibility of air-ground robots, which is important for improving mission response speed and enhancing rescue capabilities. In order to achieve the rotorcraft landing on the moving platform in the shortest time, this paper proposes a trajectory generation method for optimal lift decomposition, aiming to maximize the flight performance of the rotorcraft with finite lift. The method decomposes the finite lift of the rotorcraft to obtain the optimal three-axis lift distribution, then transforms the nonlinear acceleration constraint into a dynamic linear constraint, and finally solves the optimal time-of-flight trajectory of the rotorcraft according to the optimal control theory. The simulation results show that the proposed algorithm can ensure the accuracy and stability of trajectory planning, and the algorithm has high computational efficiency, which can meet the real-time requirements of the system in practical applications.