A thorough understanding of the various parameters that affect the vertical axis wind turbine performance and lifespan will make design this model of turbine not difficult task. This article presents a study of the blade profile effect on the aerodynamic performance of a vertical axis wind turbineDarrieus H-rotor. A complete series of simulations based on complete unstable URANS calculations are performed for a three-blade Darrieus wind turbine. Fluent’s software is used for the numerical solution. The aerofoils of blade chosen for testing were NACA 0012, 0015, 0018, 0021 and -60 pitch angle is taken as the reference case for comparison. In order to quantify the influence of the profile of the blade on the performance, the characteristics of the flow field around the rotor of the different configurations are studied. For different values of the tip speed ratio, dynamic quantities, such as torque and rotor power, are presented and analyzed. Also in this investigation of the flow flied, two parameters are carefully investigated: mesh resolution and time step size. In the analysis, it appears that these parameters affect result accuracy. Finally, the numerical result shows that the variation of blade profile directly affected directly the power production.