Abstract:Taking Yaodianzi Spoil Site in Huize - Qiaojia Expressway as an example, the flood impact assessment of spoil site in the mountainous area expressway in Yunnan is studied. The flood control standard, rainstorm flood characteristics and river course evolvement of spoil site are analyzed. The flood assessment conclusions are given through the river characteristic value calculation, flood calculation, discharge capacity calculation, backwater calculation and scouring analysis, which provides the guidance for the design, construction and management of spoil sites, and can also be referred for the planning construction of the other spoil sites in the same region.