Downstream scour of stilling basins is one of the most important factors affecting the bed stability and hydraulic performance of diversion structures and spillways. The aim of this study is to investigate the effect of a stepped reverse slope at the beginning of the stilling basin on reducing downstream scour characteristics. For this purpose, four cases including no step and step with slopes of 0, 9, 14 and 27 degrees have been numerically analyzed in Flow3D software. The RNG turbulence model was used in the flow analysis. The spillway of Chalus diversion dam located in Mazandaran province has been used as a case study. The results showed that increasing the stepped slope causes a gradual decrease in the depth and length of the scour pit and also the kinetic energy of the flow. At the highest slope investigated, the maximum depth and length of the scour pit decreased by 12.82% compared to the case without steps, causing a gradual decrease in scour, and the lowest scour depth was observed in case B with an angle of 27 degrees, which is equal to 0.102 m. The findings indicate that the use of a stepped reverse slope can be used as an effective solution to control scour and improve the hydraulic performance of stilling ponds. Numerical simulation of physical phenomena allows for a more detailed study of the flow field, velocity vectors, and pressure contours and scour pit, which is also discussed in detail in this article.