In order to study erosion-corrosion distribution of contact block surface for miter gates，we extract a partial contact block model，simplify the model，and compare and analyze the influence of different particle size，mass flow，and upstream water pressure on the distribution of the erosion area for the contact block. The results show that the wear of the concave block for miter gate is faster than that of the convex block. The erosion area of the larger sand size is mainly at the entrance of the upstream crevice，the erosion area of the medium sand size is more evenly distributed，and the erosion area of the smaller sand size is mainly at the exit of the downstream crevice. The sand particle size has a greater influence on the wear position distribution of the contact blocks，and the influence of the mass flow and upstream pressure on the wear position distribution of the contact blocks is the second.