To capture the high-quality wind energy in built environment, combined with height advantage of skyscraper and canyon wind effect of building diffuser, the vertical axis wind turbines were mounted between the building diffusers. By the means of numerical simulation, the aerodynamic characteristics of building augmented vertical axis wind turbine with different solidity and different airfoil configuration had been investigated. The results show that the building diffusers can sharply increase the power coefficient of wind turbine. The optimal power coefficient of building augmented wind turbine is 4.47 times higher than the clean one and the optimal tip-speed ratio shifts to the right. But it has intense load fluctuation and it is sensitive to building configuration. The circular configuration can decrease the influence of shedding vortex of buildings. With increasing solidity, the power coefficient of building augmented vertical axis wind turbine increases first and then decreases due to the interference between blades, and the load fluctuation and self-starting have been improved obviously. The FXLV152 airfoil contributes to decrease the fatigue cumulative damage and the NACA0021 airfoil contributes to increase efficiency of wind turbine. However, the S809 airfoil is not appreciated for building augmented vertical axis wind turbines. The numerical results provide a reference for practical application of building augmented vertical axis wind turbines.