For a typical 150QJ20 type deep-well centrifugal pump, three positions of the impeller inlet edge were designed. The whole flow field of the deep-well centrifugal pump was simulated with Fluent code based on standard k—εturbulence model and the SIMPLEC arithmetic. The static pressure and turbulent flow field were compared, the impact of the position of impeller inlet edge on the hydraulic performance was analyzed. The results showed that appropriate extend the impeller inlet edge could reduce the turbulence intensity of impeller exports and improve the flow field, also could reduce the impeller inlet diameter and increase the hydraulic performance of deep-well centrifugal pump.