The parameter influence of rotor free-wake method was presented, including blade discrete segments, vortices grid density and wake length. Several areas were made from blade root to blade tip. The inside area was segmented coarsely but the tip area was segmented more densely. The segment density of inside area has lower influence on the numerical result than that of tip area. Vortices were used to model unsymmetrical aerofoil. The density of vortices can affect the numerical result obviously. Proper density is needed and too dense vortices grid can not improve the accuracy of numerical result. For the hover and low speed flight state, 9 loops of wake is enough to get accurate numerical result, and for climb and high speed flight state 7 loops of wake is enough. The influence of time cost of these parameters was also discussed and wake length has the most influence.