Abstract: Sediment transport above the rippled bed under wave motion plays an important role in coastal landforms, but the accuracy of traditional numerical models is limited by the bottom boundary condition for sediment behavior and oscillatory factors. In order to significantly save calculation cost and maintain accuracy, an advection-diffusion sediment numerical model of single-phase flow is developed to study the vortex structure and suspended sediment movement over rippled bed under wave-induced oscillatory flow. The bottom boundary condition for sediment takes into account the acceleration effect and asymmetric boundary layer development under nonlinear waves as well as the mass conservation and phase-lag of sediment. The effects of particle inertia and wake flow around sediment particle are considered, and the SST k-ω turbulence model which is more suitable for inverse pressure gradient flow over rippled bed is selected to close the time averaged Reynolds stress. The results of numerical model agree well with the experimental data and accurately predict the periodic concentration at fixed points and the vertical distribution of average suspended sediment concentration. The results define the cut-off vorticity level and quantitatively show the periodic development of vortex center, vortex size and vortex strength. Further results reproduce the formation, development and projection of the vortex and show the development of sediment cloud.