Abstract: In views of the advance of research on the genus [WTBX]Orthotrichum[WTBZ] and according to the specimens of 350 packets collected from different parts of Xinjiang,17 species are reported in this paper.Among them 1 species (O.alpestre Hornsch.ex B.S.G.) is reported for the first time in China,and 4 species (O. hookeri Wils.ex Mitt.,O.ibukiense Toy.,O.pumilum Sw.and  O.revolutum C.Muell.) are reported for the first time in Xinjiang.All species are in 5 subgenera,6 species (O.affine Schrad.ex Brid.,O.dasymitrium Lewinsky in T.Kop.,O. hookeri Wils.ex Mitt.,O.sordidum Sull.et Lesq.,O.speciosum Nees.and O.striatum Hedw.) in subg.Gymnoporus,1 species (O.obtusifolium Brid.) in subg.Orthophyllum,5 species (O.alpestre Hornsch.ex B.S.G.,O.crenulatum Mitt.,O.pallens Bruch.ex Brid.,O.pumilum Sw.and O. revolutum C.Muell.) in subg.Pulchella,1 species (O.rupestre Schleicher ex Schwaegr.) in subg.Phaneroporum,and 4 species (O. anomalum Hedw.,O. cupulatum Brid.,O.hallii Sull.et Lesq.and O. ibukiense Toy.) in subg.[WTBX]Orthotrichum.According to these specimens,the keys to the subgenera and species are made respectively.The Chinese names,Latin names and reference literatures as well as the characteristics and geographical distribution of the species are also included.The purpose is to provide the data for the compilation of Flora Bryophytarum in Xinjiang.The studied specimens are deposited in the herbarium of College of Life Science and Tecnology,Xinjiang University (XJU) and the Institue of Botany,Chinese Academy of Sciences.

Key words: Orthotrichum, plant taxonomy, new recorded species, Xinjiang