New helical Vertical Axis Wind Turbine (VAWT) is proposed on the basis of straight blade VAWT. The dynamic numerical simulation for VAWT is completed with the computational fluid dynamics to study the aerodynamic load characteristics and analyze the influence factors. A three-dimension numerical model is established and the reliability is verified. The aerodynamic load of the helical VAWT is calculated and the effects of helical twist angle, tip speed ratio, chord length and pitch angle on the aerodynamic performance of VAWT are analyzed to seek out the optimal structural parameters. The investigation shows that comparing to the straight blade VAWT, the helical VAWT could reduce the volatility of instantaneous torque coefficient and improve the power coefficient effectively. The research could provide theoretical guidance to select the structural parameters of helical VAWT.