The South Qinling microcontinent is one of the important tectonic units of the Qinling orogenic belt. In order to study the provenance of sediments in Mesozoic graben basin in South Qinling, the authors conducted LA-ICP-MS zircon U-Pb isotopic dating on polymictic conglomerate of Tianjiaba Formation and tuff sandstone of Zhoujiawan Formation of Lower Cretaceous in Fengtai area. Two groups of dating data were obtained, which have 40 effective ages respectively. The results show that the zircon ages have five age peaks with ranges of 2 595~2 771 Ma, 1 215~1 916 Ma, 749~1 142 Ma, 424~576 Ma and 218~306 Ma, which correspond respectively to Kenor, Columbia, Rodinia, Gondwana and Pangaea supercontinent events. Based on zircon dating analyses and combined with the regional geological data, it is concluded that the North Qinling accretion-type orogen and the North China plate provided the dominant clastic materials for the Mesozoic basin in South Qinling, followed by the Yangtze plate. The North Qilian orogenic belt and the northern margin of West Qinling orogenic belt also contributed to the provenance of sediments in the Mesozoic basin of South Qinling.