The aim of this study is to establish a flood assessment index system in Mayangxi Basin, to evaluate its flood risk level, and to preliminarily evaluate the flood loss through the Depth-Loss Percentage Function, in order to provide technical support for river flood risk analysis.Firstly, linear projection processing was carried out on the data of each evaluation index by projection tracing method to obtain the comprehensive index of the flood degree in Mayangxi Basin, and then graded evaluation was carried out.Secondly, according to the HAZUS principle, the depth-loss percentage curve is established based on the post-disaster loss data of residential buildings.Finally, an insurance scheme is designed to transfer the flood loss risk of residents' indoor property in Mayangxi watershed.The research results showed that the highest flood risk area in Mayangxi Basin was Shili Village, and the risk level was Grade I.The development depth-loss percentage function can be used to evaluate flood damage quickly and accurately.The study has determined the flood risk level, which is practical and has laid a solid foundation for flood prevention in this area.