Comparing to Φ-type and H-type VAWT (Vertical Axis Wind Turbine), the amplitude changes of the aerodynamics acting on Helical-type VAWT are much smaller, so Helical-type VAWT has advantages in steady output power and avoiding fatigue of structure. Considering the characteristic of helical-type VAWT, this paper modifies the semi empirical method of calculating aerodynamic loads and compares with CFD results. A comparison is presented between CFD results and experiment results to confirm the model used in CFD. Single parameter analysis and muti-parameters analysis are carried out to study the influence of structural parameters on the dynamic torque. Based on an objective output power as 5MW, the parameters of wind turbine are adjusted, and optimal values of these parameters are determined.