Power curve is an important technical index to measure and assess the performance of wind turbines. Affected by various factors such as design and operation, power curve has been difficult to meet the standard assessment requirements of the industry and market. The power curve is not up to standard from three aspects of mechanical measurement error, backward control strategy and aerodynamic performance change. And through the calibration of blade mechanical zero angle, the use of minimum rotor angle, double PI torque control and modification of simulation models, taking the problem wind turbine as an example, the simulation results show that the above measures can improve the power curve of the unit and greatly improve the generating performance of the unit.