Abstract: Canard Rotor/Wing UAV combines the hover flight characteristic of a helicopter with high subsonic cruise of a fixed-wing aircraft. The flight dynamic model for the CRW was developed and analyzed. The momentum theory was used to build the rotor/wing slipstream model in the rotary-wing and conversion flight. The influence produced by rotor/wing slipstream on canard and horizontal tail was analyzed. In the rotary-wing and conversion flight, the flight dynamic model affected by the rotor/wing slipstream was developed. At the same time, the flight dynamic model in the fix-wing flight was developed too. The balance strategy was suggested in different flight modes. The Matlab toolbox functions were used to simplify trim calculation and model linearization in different flight modes. And the longitude dynamical stability for typical flight states was analyzed in different flight modes. The results show that the model contains the typical characteristic of the CRW, and can be used in flight control system design.