Abstract: Based on the mathematical models of the geometric contours of elbow inlet passage and siphon outlet conduit, the general software for hydraulic optimum design was developed with the geometrical parameters, and the geometric contours of elbow inlet passage and siphon outlet conduit could be drawn quickly in accordance with the principle that the average flow rate was gradually changing., and the optimum hump section of the siphon outlet conduit was theoretically analyzed. The hydraulic design of elbow inlet passage and siphon outlet conduit were optimized by the combination of one-dimensional design theory and the computational fluid dynamics (CFD) technique. For selecting an execellent model pump, detailed model tests of pump device were carried. Therefore, a high specific speed vane-type mixed-flow pump 211-80 model with high efficiency, good anti-cavitation performance and no instability running area was gained in the end. The pump device with the 211-80 model worked in a wide high-efficiency zone, and its maximum efficiency reached 79.62% at the net lift of 5.4 meters. The optimum design methods and model test results can offer the reference in large low-lift pumping station constructions.