Abstract: Sect.Duretia is a big-sized sect.of genus Boehmeria,the phylogenetic relationship of it is not very clear.The sequences of nrDNA ITS from nine species and four varieties of sect.Duretia in Boehmeria were analyzed by PCR amplification and direct sequencing.The average sequences of PCR products were about 687 bp including ITS-1,5.8S and ITS-2.By referring to sequence of Pilea notata,the genetic distance among varieties were calculated,MP tree and NJ tree was constructed to analyze the genetic relationships of sect.Duretia in Boehmeria.The phylogenetic trees based on the data set show that the B.gracilis,B.silvestrii,B.japonica and B.pilosiuscula,B.siamensis formed a monophyletic group,with bootstrap values of 76%(MP) and 89%(NJ);B.densiglomerata,B.dolichostachya,B.macrophylla var.canescens,B.macrophylla var.scabrella,B.macrophylla var.rotundifolia,B.formosana and B.formosana var.stricta formed another monophyletic group,with bootstrap values of 74%(MP) and 94%(NJ).However, B.polystachya formed a single group,it has the most distant to the other species of sect.Duretia.