In order to solve the overlarge radial hydraulic forces on the impeller of screw-type centrifugal pump with single blade, splitter blade was added. Based on Navier—Stokes equations and k—εturbulent model, three-dimensional unsteady flow field of the pump was simulated numerically to the screw-type centrifugal pump with and without splitter blade. Pressure fluctuations in the outlet of pump, radial hydraulic forces on the impeller and volute were obtained at different flow rates. The analysis results indicated that the pressure wave in the outlet of pump, radial hydraulic forces wave on the impeller and volute were always periodic in the two models, impeller blade passing frequency was the dominant frequency. Compared with the result without splitter blade at different flow rates, the period decreased to a half, the amplitudes of pressure fluctuations in the outlet of pump was smaller, the radial hydraulic forces on the impeller decreased a lot, the distribution of radial hydraulic forces on the impeller vector coordinates were more symmetry, and almost ellipses, the radial hydraulic forces on volute increased a little, but the amplitudes of which was decreased, and the high-frequency components were also fewer. The analysis results indicate that the adding of splitter blade in impeller of screw-type centrifugal pump with single blade can not only decrease the radial hydraulic forces on the impeller, but also decrease oscillations in volute as well.