Abstract: This article combines numerical simulations and model experiments to study the influence of flow field characteristics on the hydrodynamic performance of turbines in the near-field. The effect of different factors such as inflow velocity and tip-speed ratio on the wake field characteristics in the far-field is analyzed. The research results show that the relative error of power coefficient between the numerical simulation result（0.37） and the experimental result（0.36） is 0.3% at the designed tip speed ratio, and the relative error of drag coefficient between the numerical simulation result（0.73） and the experimental result（0.76） is-4%. There are significant threedimensional flow phenomena at the blade tip of the tidal turbine, there is a radial velocity（0.24 m/s） at the front of the turbine disk which flows from the blade root to the tip, and there is a radial velocity（0.14 m/s） at the rear of the turbine disk which flows from the blade tip to the root. The downwash flow velocity near the wake zone of the blade tip causes a decrease in the energy conversion efficiency of the turbine. The inflow velocity has no a significant impact on the recovery of axial velocity in the wake region; In the near wake region（within 5D distance from the disk）, with the increase of tip-speed ratio, the recovery of axial velocity in the wake shows a gradually decreasing trend. When the distance from the water turbine disk exceeds 10D, the tip-speed ratio does not have a significant effect on the recovery of axial velocity in the wake. However, the increase of tip-speed ratio will shorten the existence time of the blade vortex and make the location where the blade vortex is broken closer to the water turbine disk.