Tadong group is a set of high greenschist facies- amphibolite facies metamorphic rock series, which is considered to be a part of the Precambrian metamorphic basement of “Songnen- Zhangguangcailing block”. However, the time of its for Mation is uncertain. This study conducted zircon U- Pb (LA- MC- ICP- MS) dating to determine the chronology of the biotite monzogneiss of the Zhudundian For Mation in the Tadong rock group. In 105 tests, 104 effective measurement points were between 239 Ma and 2690 Ma. The age spectrum shows Many age groups: 2690 ~ 2679 Ma ( n =2), 2509 ~ 2304 Ma ( n =8), 2287~2173 Ma ( n =5) , 1924~1836 Ma ( n =4), 1428~1352 Ma ( n =2), 1171~1017 Ma ( n =3), 997~929 Ma ( n =12), 922~822 Ma ( n =40), 812~793 Ma ( n =14), 745~738 Ma ( n =2), 279~239 Ma ( n =8). Early Precambrian zircons accounted for ~18%, Grenville orogenic period zircons accounted for ~53%, Rodinia supercontinent cracking stage zircons accounted for ~14%. The age concordance of the zircons shows that the Precambrian zircons all lost Pb to varying degrees. Two age segments, 1428~239 Ma and 2690~1836 Ma, were respectively used for data processing, and it was found that the incongruent offline intersection of the former was 476±84 Ma, while the incongruent offline intersection of the latter was 1711±210 Ma, which May reflect two important tectonic ther Mal events. Zircons of late Paleozoic age are characterized by Mag Matic zircons whose Th/U ratio is generally greater than 0. 1. However, their complex CL i Mage features, including cloud, flow, wedge and fir leaf- like rings, have regular shapes, indicating the result of modification for later ther Mal events. Based on previous research results and regional geological construction characteristics, it is suggested that the Main body of the Tadong rock group was formed in the Late Neoproterozoic, which May be a response to the cracking of the Rodinia supercontinent and May have undergone structural transfor Mation events at ~516 Ma, ~476 Ma and ~426 Ma . It May be a structural complex rock at the end of the early Paleozoic period, which was influenced by strong ther Mal events in the later period of ~260 Ma. The existence of a large number of early Precambrian detrital zircons supports the understanding of the existence of the ancient basement of the “Songnen- Zhangguangcailing block”.