As a kind of general fluid machinery, centrifugal pump undertakes the task of fluid transportation and energy conversion. In order to obtain a centrifugal pump with double volute with excellent hydraulic performance, the design of volute is also a part that cannot be ignored. In this paper, the main design parameters of the volute are selected in the hydraulic design process, and multiple groups of orthogonal tables are established. The influence of the main design parameters of the double volute on the performance of the whole pump is studied through numerical calculation. The numerical results show that the throat area should be selected according to the high efficiency area of the impeller so that the highest efficiency point of the impeller matches the lowest loss point of the volute, while increasing the volute base circle diameter and tongue angle can increase the hydraulic efficiency by about 0.76% and 0.16%, and reducing the thickness of the vane can increase by about 0.42%. Overall, the optimized hydraulic efficiency of the double volute centrifugal pump can be increased by about 1.7%.