The vertical distribution of suspended sediment is an important and fundamental parameter for calculating the rate of suspended sediment transport. While empirical formulas and analytical solutions have been developed to calculate this parameter, their application is often limited by simplifying assumptions regarding flow conditions, bed characteristics, and sediment properties. The literature review showed that no comprehensive studies have been conducted on the numerical simulation of the distribution of SSC. This paper aims to present a comprehensive numerical simulation approach to predict the vertical distribution of suspended sediment. In this study, the results of the Flow-3D numerical model are first calibrated and validated using a valid laboratory data set, and after ensuring the performance of the numerical model, flows containing high concentrations of suspended sediment load are simulated. The effect of changes in the parameters of sediment diameter, suspended sediment concentration, and bed roughness on the distribution of suspended sediment concentration will also be investigated. The findings of this research not only contribute to a deeper theoretical understanding of sediment transport processes, but also provide a powerful and practical tool for environmental engineers and managers in predicting and mitigating the challenges associated with suspended sediment in various aquatic environments. Also, given the aforementioned limitations for laboratory and field studies in the field of suspended sediment load transfer, this research fills important scientific gaps in the accurate prediction of vertical suspended sediment distribution.