Abstract: Aiming at the problem of low efficiency when jet pump was used for fracturing fluid backflow, and using the mixture multiphase flow model of the Fluent 16.0 software, the numerical simulation on the jet exhaust sand pump was carried out in this study.The impacts of initial concentration of the solid phase on the internal flow field, performance and efficiency in the row of sand pump were analyzed.The results showed that the higher the initial concentration of the solid phase, the higher the potential flow core, and the position of the solid liquid two-phase mixing was transferred to the outlet of the pipe.With the increase of the initial concentration of the solid phase, the concentration at the exit of the diffusion tube deviated from the theoretical value, and the greater the concentration, the greater the deviation, and reached 17.62% when the initial concentration was 20%.The existence of sand grains allowed the characteristic curve of the sand discharge jet pump were moved down.Under the conditions of the initial concentration of solid phase 20%, the flow ratio M was 1.2, compared with the flow ratio M 0.3, the efficiency and pressure ratio decreased 52.38% and 60.32% respectively.Under the conditions of same flow ratio (M=0.7), when the initial solid concentration was 20% compared to the single-phase flow, the efficiency and pressure ratio decreased by 25.92% and 26.08% respectively.