To improve the accuracy of wind measurement, computational fluid dynamics is adopted to simalate the impact of wind turbine blades with and without T-spoilers on the outflow field distribuation and the wind speed and direction measurement on the top of macelle. The simulation is arried out on a 5 MW wind turbines when the rated wind speed is 10.5 m/s and the rated speed of blades is 11.34 r/min. The calculation results show that the blades with T-spoilers have greater impact on the accuracy of anemometer and wind vane on the top of nacelle. Therefore,it’s recommended to move forward the wind measurement equipment 0.3 m and elevate them 1 m relative to the original position so that the measurement accuracy meets the design requirements.