Abstract: Qinling-Dabie orogenic belt(DOB)represents the composite convergence zone between the North China and the Yangtze blocks(NCB and YB)．It is in doubt that Qinling orogenic belt(QOB)is composed of the southern margin of NCB(SNCB)，northern QOB(NQOB)，southern QOB(SQOB)and the northern margin of YB(NYB)；Shangdan fault zone between NQOB and SQOB was a megasuture between NCB and YB during Neopmtemzoic-Paleozoic period；and the Mianlue fault zone，a subsuture between SQOB and NYB，was formed within the Yangze plate during the Late Paleozoic．Th geochemical characteristics of mantle—derived rocks provide some new evidence for DOB subdivision in the present paper．Actually，there are abundant mafit-ultra-mamic rocks distributed in different units of Dabie orogenic belt since the Late Paleozoic For example，along the Tonghai-Shangcheng fault zone occur the Chuqiurniao-Wangmuguan gabbros of the Hercynian；in both northern and southern Dabie complex outcrop many post-collisionally mafites and ultramafites of the earLy Late Yanshanian；and in centra1 and southern Dabie orogenic belt present volume mumber of the basalts of the late Late Yanshanian．Geochemical research indicates that these mantle-derived rocks are featured by enrichment of Sc and Cu，depletion of MgO，with higher Rb／Sr，Ba／St，Ba／La， Nb/Ta and Yb/Hf ratios, as well as 1ower Zr/Hf ratio. These characteristics are similar to those of the mantle in Yangtze block，and can be further compared to those of the mantle in southern Qinling orogenic belt This result has been supported by the results，obtained from the research in geology，structural geology，petrology，geophysics and isotopic geochemistry for DOB，which suggests that Tongbai-Shangcheng-Mozitan-Xiaotian fault zone in DOB be an eastern extension of the Shangdan fault zone in Qinling orogenic belt．Based on the synthetic information，it is concluded that Dabie orogenic belt developed from Yangtze mantle and belongs to the eastern part of southern Qinling orogenic belt．