In order to research the influence of the web deflection on the bend-twist coupling characteristics of large wind turbine blades, the CAD model of NREL 5 MW blade is established based on NX secondary development, the aerodynamic loads of the blade are obtained by CFD method, the blade bendind angle and twisting angle are solved by the node displacement method to analyze the influence of web deflection for bend-twist coupling blade. The results show that the offset web helps to achieve the bend-twist coupling of blades. Under the action of aerodynamic load, the bending and twisting angle both increase along spanwise direction of blade gradually, and reach the magnitude at the tip of the blade; in forward bias, negative correlation between twist angle and offset, reverse bias is the opposite; positive bias blades bend-twist coupling coefficient is decreasing trend with the increase of deflection angle, reverse bias blade are greater than the conventional blade.