A deformed metamorphic dome and a great granite body outcrops in the Laojunshan area, Southeastern Yunnan.The study area attracts great attention of many geologists because of its special tectonic position and many Tin Tungsten polymetallic deposits.The set of metamorphic rocks is also a research focus, and its tectonic evolution history and structural significance are still unclear up to the present.LA ICP MS zircon U Pb dating was conducted on the granitic gneisses from the Paleoproterozoic Mengdong Group, Late Silurian Nanwenhe gneissic granite, and Neoproterozoic Xinzhai Formation.Six samples from granitic gneisses of the Laojunshan metamorphic complex yielded three magmatic zircon groups， and the 206 U/238 Pb concordant age ranges are 4024±19Ma, 4077±15Ma, and 4168±35~4106±096Ma, respectively.Combined with the crystal features, CL images, concordant of U Th Pb ages and the corraltion index, the dating ages range from 416.8Ma to 4024Ma of metamorphic rocks in Laojunshan area, indicating that these rocks experienced an extensively Early Devonian magmatic event， and probably recording the continental syn collision orogenesis in the study area, ie. the Guangxi movement; The age of 483.5±7.4Ma from the zircon core probably reveals the beginning time of the regional Caledonian movement. Based on the previous geochronological data of metamorphic rocks in this area, the inherited zircon cores with age group of 6266Ma,7159Ma and 7924Ma further demonstrate that there should have Neoproterozoic igneous rocks and Paleo proterozoic metamorphic crystal basement in the Laojunshan area, southeastern Yunnan Province.The Neoproterozoic magmatic event, developed extensively from western Guangxi southeastern Yunnan to Dayaoshan Ailaoshan region, further suggests that the Neoproterozoic rift and magmatic belt of South China were likely to be integral with each other in the southwestern margin of the Yangtz block.And the 2194Ma of dating zircon rim records a large scale extensive magmatism and mineralization event during the Late Triassic in South China block