Because of unreasonable design of double-volute splitter in ES250-370 double-suction pump, its shaft was bent which lead to wear and tear of the seal. According to the basic principle of double-volute pump design, three different double-volute splitter schemes were put forward; the reason of radical force and the problem of original double-volute were analyzed. Based on the RNG k-εturbulent model provided by CFX software and Simple algorithm, double-volute splitters from three different improved schemes were simulated. Static pressure distribution of different volutes were obtained, the axial stress and radical force of the pump were calculated as well. Steady numerical simulation and experimental results show that, compared to the original splitter, the rated point efficiency of No.3 splitter is increased by 7%, and radical force is balanced effectively and the axis stress is the minimum, while keeping the hydraulic performance. So No.3 is the best design of the three options. Splitter starts from the fourth cross section of double-suction pump and ends with eighth cross section, and it meets the logarithmic curve equipment. A method of designing the splitter for double-volute centrifugal pumps was provided for the pump designer.