To study the flow field distribution and particle trajectory of reamer for a cutter suction dredger working at different rotational speeds and traversing velocities.In this paper,a unidirectional fluid-solid particle coupling numerical simulation of the excavation process of a certain type of reamer is carried out.The flow field are solved using the Eulerian description and the soil particles are tracked using the Lagrangian description to obtain the flow field distribution pattern and particle motion trajectories for the corresponding operating conditions of this reamer.The results show that when the rotational speed is 30 r/min and the traverse speed is 0.50 m/s,the reamer flow field is most stable and particle suction efficiency is higher.The research in this paper has certain reference value in understanding the working principle of the reamer,optimizing the cutting effect and other aspects.The research results can provide reference for the optimized construction and future promotion of the reamer for cutter suction dredgers,so as to better meet the engineering needs in practical applications.