///The Xiangfan-Guangji fault (XGF) which separates the Dabie orogen belt (DOB) from the Yangtze block is the south boundary fault of the DOB. The XGF is divided into two parts by the Jianghan rift basin. New field structural data, 40Ar/39Ar ages, zircon LA-ICP-MS ages and sedimentology evidence indicate that the XGF have experienced twice significant southward thrusting since Middle Triassic: 40Ar/39Ar ages indicate that both the XGF and the Huwan detachment, south and north margins of the DOB respectively, were formed contemporaneously as a result of the initial extrusion of UHP from mantle to lower crustal level during the continental-continental collision stage in Early Triassic (about 240~231 Ma); the second apparent thrusting was in Middle-Late Jurassic (about 160~140 Ma) before the DOB’s thermal doming extension for the granitic intrusion during this period wasn’t involved into deformation.