Abstract: A set of low-amphibolite facies metasedimentary stratum with the age undetermined is exposed in the Xiaobianhe-Changba area,Mianlue tectonic belt of the South Qinling orogeny. The formation of the era was classified as Paleoproterozoic,Early Paleozoic,Silurian-Triassic,Devonian etc, due to the long-standing controversy over its formation and the lack of accurate chronological evidence. In this paper, the study of LA-ICP-MS zircon U-Pb chronology of metamorphic clastic rocks is carried out on the metamorphic clastic rocks in this area, and a sample of zircon measuring points is completed with a total of 80 points. The metamorphism is obtained in the Xiaobianhe-Changba area, in which the minimum age-weighted average of metamorphic stratigraphic units in Xiaobianhe-Changba area is 576.5+12.4 Ma, and the age of main clastic zircon ages is between 850 Ma and 658 Ma. Based on the previous data,it is considered that the sedimentary age of metamorphic stratigraphic units should be Early Paleozoic in Xiaobianhe-Changba area;the provenances mainly come from the volcanic rocks in the Mianlue tectonic belt, the Neoproterozoic magmatic rocks in Bikou block in the northwestern margin of the Yangtze block;their sedimentary events correspond to the Early Paleozoic sedimentary process of the extensional rifting in Mianlue tectonic belt and the northwestern margin of the Yangtze block.