Abstract: In order to study rotor-stator interaction with different tongues of the centrifugal pump, the three-dimensional unsteady flow in the centrifugal pump with long-tongue, middle-tongue and short-tongue respectively, was simulated numerically using the dynamical subgrid-scale models. Variable characters of pressure fluctuation and radial hydraulic force on the impeller and volute with different tongues were achieved with a comparison was done. The results indicate that: as a result of the rotor-stator interaction, the distributions of the radial hydraulic force on the impeller vector coordinates have a obvious character of hexagonal star with different tongues under different running conditions and the distributions of the radial hydraulic force on the volute vector coordinates are presented ellipse using different tongues under different running conditions；the head increases and high efficiency area of the pump broaden using short-tongue; the radial hydraulic force on the impeller and volute changes with time; the pressure fluctuations near tongue and the radial hydraulic forces on the impeller of pumps decrease using middle-tongue and short-tongue.