Abstract: In order to investigate the parameters affecting the performance of annular jet pumps and improve their sediment discharge capacity, a numerical simulation on the internal flow field was conducted using STAR-CCM+ software, in which the VOF (Volume of Fluid) model and the Realizable k-ε turbulence model were used and the sediment phase was simulated by a shear-thinning non-Newtonian fluid.The results demonstrated that increasing the area ratio (defined as the throat cross-sectional area to the nozzle outlet area ratio) can significantly enhance the sediment discharge capacity of annular jet pumps.The nozzle installation angle influences the energy loss of the pump, thereby affecting its sediment discharge performance.For the studied model, when the area ratio was 12.15, the optimal nozzle installation angle was 32, and when the area ratio was increased to 25, the optimal angle was 28°.These findings provide valuable insights for the design of suction systems in large jet trenchers used in marine engineering applications.