The present study deals with the computational analysis of a model of a small horizontal axis wind turbine using CFD Simulation. A three dimensional computational model of the rotor system is created and simulation has been carried out using Realizable K-ɛ turbulent model. The analysis has been carried out at various wind speeds in the range of 4 m/s to 12 m/s to study the variation of torque, axial thrust and power with wind speed. The effect of the twist of the blade on the performance of wind turbine is studied. The flow field characteristics around blades at a section placed on the mid of blades have also been studied. The results show that the untwisted blades give a better performance than twisted blades for the studied conditions [tip speed ratio =6 and Reynolds number range (16000- 51000)] in terms of power, torque and thrust force and pressure distribution around blades for the range of velocities tested.