Abstract: In order to study the influence of the cross section variation of a square pier on local scour characteristics, we established a 3D mathematical model of the local scour around the pier and carried out a simulation study on the scour characteristics around the square pier under different stepped protruding widths and corresponding slopes. The results show that compared with the square pier, the structure with a certain stepped protruding width in front of the pier has a certain effect on scour reduction, but the effect does not increase with the increase of the protruding width, and the effect is optimal when the protruding width in front of the pier is about 2/3 times of the width of the pier. At the same time, through the stepped protruding width, the inclined slope surface is increased based on section optimization. It is concluded that with the increase of the protruding widths, its reduction effect increases with inclined slope height under the condition of bed surface more than 0.4 times of the water depth, the effect of which is superior to the structure of the protruding widths and its maximum reduction rates are as high as 38%. The results can provide a reference for the research on the integration of pier structure form and scour protection, especially for the optimization of large-scale pier foundation structures.