In order to investigate the hydraulic performance of elbow inlet conduit, the three-dimensional fluid flow inside an axial-flow pumping system was simulated based on the Reynolds time-averaged Navier-Stokes equations, the RNG k-ε turbulent flow model and the law of the wall. To verify the accuracy and reliability of the calculation results, a model test was conducted on the high-precision hydraulic machinery test bed. It was found that the calculated results agreed well with the measured results. The hydraulic performance parameters of elbow inlet conduit were analyzed quantitatively considering the hydraulic interaction of inlet conduit and impeller. The stability and uniformity of flow were analyzed by using static distortion index of outlet section in elbow inlet conduit. The mathematical model of static distortion index and flow rate coefficient was established with the method of regress analysis. The stability and uniformity of flow were good under the high efficiency conditions, while it was the worst under the large operating condition. The different operating conditions of pumping system had little effect on the velocity-weighted drift angle of outlet section. The maximum difference of velocity-weighted drift angle was 0.91°. The average static pressure ratio of linear contraction segment was 0.943, while the average static pressure ratio of elbow segment was 0.826. The average hydraulic efficiency was 99.215% for elbow inlet conduit. The uniformity of cross section was affected under the condition of boundary constraint. The conversion rate of pressure energy and kinetic energy was high in the elbow segment. The important technology of optimization design is elbow segment for elbow inlet conduit.