The theoretical analysis and numerical simulation method were used to study the influence of inlet guide vane on the hydraulic performance of axial-flow pumping system. The inlet guide vane was designed based on design requirements. The three-dimensional internal flow of axial flow pumping system was simulated in different installation angles of inlet guide vane. Overall performance curves of axial-flow pumping system with adjusted inlet guide vane were obtained and the multiple non-liner regression prediction mathematical models of the hydraulic performance were established based on the results of numerical simulation and velocity triangle analysis. Compared with the pumping system without inlet guide vane, the hydraulic performance of pumping system with inlet guide vane changes little in the high efficiency area and small flow rate condition, but the efficiency of pumping system drops greatly because the hydraulic loss of inlet guide vane increases greatly in the large flow rate condition. With the increase of positive installation angle of inlet guide vane, the high efficiency operating condition is offset to small flow rate and the whole efficiency curves of pumping system would drop. While, with the decrease of negative installation angle, the high efficiency of pumping system increases firstly then decreases. The flow rate doesn’t change in the high efficiency operating condition of different negative installation angles.