<p>Double-channel volute is usually applied to the turbine of vehicle turbochargers to further enhance the performance of engines. Previous studies pay less attention to the parametrization design of turbine volute profile. Deriving parametric equations for the cross sections design and the spatial coordinates calculation of turbine volute can improve the design accuracy and efficiency. In this study, a parametric modeling method of double-channel turbine volute with arbitrary area ratio is proposed. It selects one channel of the double-channel turbine volute for design, mainly including the spiral segment, the pre-swirl segment, and the inlet segment. For each segment, parametric equations are derived for the cross sections design and the spatial coordinates calculation. By giving different flow rate ratios of the double-channel volute, two channels with different sizes are generated. To validate the parametric modeling method, experimental measurement and numerical simulations are carried out for the turbine stages with the volutes designed by the proposed method. It is found that the averaged improvement of the calculated adiabatic efficiency is about 4.0% for the symmetric double-channel volute relative to the single-channel volute. This suggests that the parametric modeling method is applicable and efficient for the development of double-channel turbine volute.</p>