Aiming　at　the　problem　that　structural　damage　identification　is　greatly　disturbed　by　external　random　loads,　this　paper　proposed　a　mean　curvature　difference　method　of　the　normalized　mean　displacement.　Firstly,the　mean　value　of　the　displacement　response　of　the　multi-sample　group　was　used　as　the　damage　characteristic　function,and　the　influence　of　noise　was　preliminarily　eliminated.　Then,　the　curvature　of　the　displacement　mean　curve　was　normalized,　and　the　curvature　difference　was　calculated　to　reduce　the　influence　of　random　loads　significantly.　Finally,the　average　curvature　difference　of　adjacent　measuring　points　was　used　as　the　damage　identification　index　to　judge　the　damaged　unit.　Simply　supported　beam　bridge　and　self-anchored　suspension　bridge　were　taken　as　examples　to　verify　the　proposed　method　from　both　theoretical　and　numerical　model　aspects.　The　influence　of　different　degrees　of　noise　on　the　recognition　effect　was　also　analyzed.　The　results　show　that　the　proposed　method　can　identify　the　damage　of　the　structure　under　any　moving　load,　and　is　suitable　for　the　damage　identification　of　the　structure　under　the　random　load,　which　has　good　anti-noise　performance.　©　2023　Chinese　Vibration　Engineering　Society.　All　rights　reserved.