The study of the flow characteristics of the solid-fluid two phase flow in the cutter suction dredger is very important for exploring the slurry formation mechanism and optimizing the operational parameters. In this study, standard k-ε model and Multiple Reference Frame are applied to numerically simulate flow field in and around the cutting system, then with the steady convergent result of the simulation as the initial condition, Discrete Phase Mode is used to solve the particle motion equation by fully coupling the continuous phase and the particles. The influence of suction flow velocity and cutter’s rotating speed on particles suction are analyzed, and effectively suctioned particles numbers are also quantitatively studied. The simulation result shows that the DPM model is able to simulate the movement of particles in and around the cutter suction dredger’s cutting system, in the fluid flow filed velocity vector and pressure distribution on different planes show different characteristics, and under higher suction velocity and lower cutter rotating speed more particles are suctioned into the suction inlet. The results can help better understand flow characteristics of solid-fluid 2-phase-flow of cutter suction dredger’s cutting system, and provide theoretical support for relative system design and operational parameters optimization.