We　achieve　a　dynamic　update　of　the　authentication-tree　through　creating　the　sub　tree　and　dynamic　update　of　the　key.　In　the　original　signature,　the　number　of　the　signature　influence　the　scale　of　the　authentication-tree,　and　the　increase　of　the　number　of　signature　makes　lower　efficient.　In　our　scheme,　the　number　of　signature　is　not　affected　by　the　scale　of　the　authentication-tree.　In　addition,　the　paper　do　a　safety　analysis　to　the　improved　authentication　Merkle　tree　signature,　the　results　show　that　the　signature　of　the　improver　Merkle　authentication　is　as　safe　as　the　original　Merkle　authentication　signature　tree,　and　as　used　key　management　according　the　time,　the　The　signature　also　has　forward-secure.