A manipulation assignment strategy of full-mode flight based on unmanned tilt-rotor aircraft flight dynamics model trim and small perturbation linearization processing results was presented, and its manipulation efficiency was analyzed for different flight mode. The control efficiency matrix coefficients were solved with an objective optimization function specification of multi-object nonlinear control method. A difficult problem that was the manipulate redundancy as the flight mode changes in the process of flight control was overcome. A unified flight controller was designed with the help of manipulation allocation strategy, without having to design a controller for different flight mode. The design difficulty of the flight controller is effectively reduced. A full-mode of flight simulation is given out, in which a stable flight control is achieved with a linear PID controller. Simulation results demonstrate the credibility of the tilt-rotor aircraft flight dynamics model and the effectiveness of the manipulation assignment strategy.