Abstract: A mathematical model for suspended sediment deposition has been developed based on an Eulerian-Lagrangian approach to explore the trajectories of suspended sediment particles in open channels. This model adopts a standard k-ε turbulence model for calculation of the turbulent flows and it calculates sediment particle tracks using a Lagrangian method and considering various forces on the particles, including: the effective gravitational force, drag force, virtual mass force and Saffman lift force. Compared with the traditional diffusion model and two-fluid model, the new model avoids the limitation on inflow sediment conditions that must be specified by measured sediment concentration distributions. Its prediction accuracy and reliability have been verified using a classical experiment of suspended load transport with net deposition, including a comparison between the predicted longitudinal variations of sediment concentration and measured ones. A non-monotonic vertical profile of sediment concentration that observed from the experiment has been also predicted with a good accuracy.