Abstract: Based on blade element momentum（BEM）theory,several modification models are considered,including dynamic stall,wind shear and tower shadow effect and so on. The MATLAB simulation program is developed to calculate the unsteady aerodynamic load. Taking NREL 5 MW wind turbine as example,the aerodynamic characteristics of floating horizontal wind turbine are studied. The results show that the modified models are necessary for the correctness of simulation of aerodynamic loads. The motions of the floating foundation may increase the output power of wind turbine. Meanwhile,the amplitude oscillations of aerodynamic load are larger,which lead to the instability of the output power. The blade-pitch fault makes the output power more unsteady.