Abstract: On the basis of time-averaged N-S equation and k-ε turbulent model, the inner flow of double-suction impeller was calculated in 3-D body-fitted coordination by applying SIMPLEC algorithm. The velocity, pressure distributions in impeller were obtained and used to analyze pump performance under different working conditions. The calculation results indicate: in double-suction centrifugal pump impellers, the static pressure gradually increases from the inlet to outlet; in any mid-plane between the shroud and symmetric plane, the static pressure in the pressure side is obviously larger than that in the suction side of vanes, and the pressure gratitude increases as the location of mid plane changes from the symmetric plane side to the shroud side; the flow is symmetric and there is no axial velocity on the symmetric plane; the static pressure distribution on the outlet of impeller is much more uniform in designed working condition than in off-design working conditions.