To investigate the effect of adding the winglet or enlarging the aspect ratio of the blades to the aerodynamic performance of H-VAWT, it calculated and analyzed the impaction of different designing parameters of H-VAWT to the tip loss. It based on the aerodynamic performance of the finite blade length H-VAWT, the aerodynamic performance of the related infinite blade length H-VAWT was compared with it, the related difference of aerodynamic performance got through comparing the related difference of the aerodynamic performance, the affection of different designing parameters-solidity and airfoil to the tip loss of H-VAWT was analyzed. By means of comparing the aerodynamic performance of H-VAWTs generated by different aspect ratios, the improving effect of the aspect ratio to the tip loss of H-VAWT was analyzed and concluded. The total results illustrated that: no matter how the solidity of the H-VAWT and the airfoil adopted of the H-VAWT blade was, when H-VAWT worked at high tip speed ratios(λ≥1.60), it was necessary to adopt the measures that decreasing the adverse affection of tip loss to improve the aerodynamic performance of H-VAWT; when H-VAWT had large solidity(σ≥0.96) or adopted thick airfoils, it was also necessary to add wing let or enlarge the aspect ratio of the blade to decrease the adverse affection of the tip loss; the effect of enlarging the aspect ratio to improve the aerodynamic performance of H-VAWT was finite, based on the designing requirements and the other geometry parameters' limitation, the value of aspect ratio was suitable at 5≤μ≤20.