There are a lot of spinel-lherzolite xenoliths in the Taiyangshan Mesozoic basalt in Ningyuan, Hunan province. Five samples of chrome spinel, forsterite, chrome-diopside, orthorhombic and whole rock were picked out under microscope from the brocken pieces, were analysesed in the Isochronology Center, Tianjin Institute of Geology and Mineral Resouces, Geological Survey of China. A Sm-Nd whole rock-single mineral isochron age of 2702 + 19 Ma was got. According to this result and having synthesized the data others got before, writers consider the lithosphere of southern China was vertically multiplicated. From bottom upward in order: upper mantle mat, crystallized basement, folded basement, folded cover and sedimentary cover. Among five structural layers, upper mantle rock plays a role of motherboard oushion, was formed at Neoarchaeoid is the oldest rock in this district.