Abstract: The compound helicopter has gained more and more attentions so far, but the analysis method available is limited. Employing the free-wake arithmetic and vortex lattice method(VLM), a program for compound helicopter aerodynamic computation was developed. Using this program, interactions between the rotor and the wing were computed in different advance ratios and wing locations. From the computation results, some conclusions can be made: for the compound helicopter described, the interaction between the wing and the rotor isn-t sensitive to the wing location in high velocity, except the rotor torque; In low flight speed, the interaction is more complex, and needs more researches; Because of the dissymmetrical structure of the rotor wakes, the spanwise lift distribution of the wing is dissymmetrical, and it will cause a rolling torque.