Abstract: Flood control projects are important facility for safe operation of tailings pond.Tailings pond slope overland flow calculation is the main method for flood calculation,and the hill slope roughness is an important factor influencing tailings pond slope overland flow.In order to study the influence of the hill surface roughness on the overland flow of the tailings pond,especially on the flood peak discharge,MATLAB software is used to calculate the slope overland flow under different hill surface roughness and analyze the variation of flood peak discharge under different hill surface roughness.The calculation results show that the change of hill surface roughness has a great influence on the flood peak discharge,and the effect of roughness reduction is particularly obvious,which should be taken into serious account when tailings pond is designed.