Based on the designed vertical axis wind turbine, the CFD technique was used to analyze the flow field and aerodynamic performance. According to the analysis results,the influence of the tip speed ratio, blade, blade angle and other factors on aerodynamic performance of wind turbine was studied.It is obtained that the wind energy utilization rate is maximum with tip speed ratioλ=2, wind speed is about 12 m/s.It provides reference for the optimization design of fan impeller.