According to the field survey of the damaged engineering structure suffered the flood on July 23rd in Danfeng County, it is analyzed that the failure modes and characteristics of elementary and secondary schools, village and small town residence, roads, bridges and others under the effect of extreme loads, such as debris flow , mountain torrent, landslide and so on. Natural environment must be practically protected in the mountainous area easy to suffer natural calamities. What’s more, good flood carrying capacity of the channels must be assured. Site selection of all different kinds of projects must be serious and careful, and they cannot be located in the ditch mouth of mountain torrents, occupy the flood carrying channels, or be too close to channel bank. Protection works must be set up for the key projects, and the revetment, retaining wall, longitudinal dike, spur dike and others should be fully utilized to resist, eliminate, or weaken extreme loads. It is necessary to strengthen the quality supervision of all diverse kinds of projects in the villages and small towns, perfect the design and construction process, and enhance the anti-scouring capability of the foundation of the projects.