Through the analysis of the aerodynamic interference of the downwash on wings under different intensities on both sides of the rotor of the composite high-speed helicopter, a certain reference can be given for the design and optimization of the aerodynamic shape of the similar configuration helicopter. Based on the unsteady momentum source method, numerical simulation of the flow field of a composite high-speed helicopter in hovering and forward flight states is carried out, and analysis the aerodynamic effects of different downwash on both sides of the rotor on wings，and study the effect of aerodynamics by changing the height of the rotor disc and the aspect ratio of wing.The results show that: when the composite high-speed helicopter flies forward, with the increase of the rotor disc height, the peak lift difference between the two sides of the wing decreases, and the peak value falls at a lower speed; with the increase of the wing aspect ratio, the lift difference between the two sides decreases. The peak value decreases, and at the same speed after the peak value, the more slender wing, the smaller lift difference between the two sides.