Abstract: In order to explore the effect of web deflection on modal,strength and buckling characteristics of the bend twist coupling blade,Taking the blade of NREL 5 MW wind turbine as the research object,the blade CAD model was established based on the secondary development of NX. The blade surface pressure distribution was obtained by CFD method for fluid-structure coupling analysis.The results show that natural frequencies of the bend-twist coupled blade are lower than the conventional. The blade shear stress is less than the conventional blade when the main beam of pressure surface deflects to the leading edge. Conversely the trend of the equivalent stress and strain on the blade surface is the same with the deflection angle. The effect of decreasing range and unloading reduction of load is related to web deflection;The blade tip displacement increases with the increase of web deflection. The deflection of the main beam on the pressure surface to the leading edge can enhance the critical buckling load of the blade,the critical buckling load of each blade is smaller than that of the conventional structure blade when the reverse deflection is applied.