A fluctuating inflow around the surface of rotor blade in the spanwise direction presents a more significant challenge in the performance of wind turbine. In this paper, three-dimensional (3D) experimental and computational investigations of a straight-bladed VAWT (Vertical Axis Wind Turbine) are proposed and analyzed with two straight blades. In wind tunnel experiments, LDV (Laser Doppler Velocimeter) system is presented to investigate the influence of spanwise direction on the straight bladed of NACA0021 symmetric airfoil in unsteady wind condition. In numerical analysis, 3D transient CFD (Computational Fluid Dynamics) models have been performed to simulate the flow field characteristics of VAWT at the same experimental conditions as wind tunnel experiments. From comparing the results of wind tunnel experiments and numerical analysis, it is found that momentum amount is the largest at the blade center height and the smallest at the blade tip. Furthermore, it is well able to predict the experimental results using CFD model based on k- epsilon Shear Stress Transport turbulence model. (C) 2016 Elsevier Ltd. All rights reserved.