In order to further study the hydraulic performance of flow passage components for S –shaped shaft extension tubular pumping system, the whole flow passage of pumping system were simulated based on the CFD technology under multiple operating conditions. The inner flow pattern and hydraulic performance of flow passage components were analyzed. Focusing on details of flow field, the flow characteristics in the impeller and guide vane were analyzed under three different operating conditions (the small flow rate condition KQ=0.368, the best efficiency condition KQ=0.490 and the large flow rate condition KQ=0.613). The static pressure of pressure surface near shroud is larger, and the static pressure of suction surface near hub is larger than that near shroud. With the increase of spanwise location value, the differential pressure between pressure surface and suction surface increases gradually. The static pressure of guide vane surface increases from inlet section to outlet section at KQ=0.490. With the decrease of flow, the recycling circulation ratio CH decreases firstly then increases, and the minimum ratio CH was 0.031 at KQ=0.490. The accuracy and effectiveness of numerical results were verified by the physical model test. The test results show that when the flow coefficient KQ=0.443 and the head coefficient KH=0.828, the highest efficiency of pumping system is 83.55% at the blade angle -2°.