The energy dissipation structure of the hopper has an important influence on the overflow loss of the trailing suction hopper dredger. Three kinds of inflow structures of the hopper，i.e. the prototype，the colliding，and the 45-degree high-lift colliding，are compared by the numerical calculation method in this paper. The calculation results show that：1）Compared with the prototype，the vortex distribution of the flow field in the hopper with the colliding and the 45-degree high-lift colliding is relatively concentrated.2）The outflow diffusion range is located in the zones near the outlet for the inflow pipe. 3）The velocity and the turbulence intensity in other zones of the hopper are smaller than the prototype，the turbulence intensity attenuation is more obvious especially in the area near the overflowing cylinder. This shows that the colliding and the 45-degree high-lift colliding structures have a certain energy dissipation effect，which will be conducive to sand sedimentation in the process of loading of the hopper，and achieve the purpose of improving the loading efficiency.