Abstract: The Middle Proterozoic Tuanliangzi Formation, widely exposed in the Yunxian-Jinghong area of western Yunnan, consists of a set of low and medium metamorphic sedimentary rocks intercalated with the Yangtze basement rock series. Its formation age, sedimentary filling sequence and tectonic attributes have been controversial. The Tuanliangzi Formation exposed in Manwan area of Yunxian County contains basalt and sericite quartz phyllite, several meters in thickness. In this study, the LA-ICP-MS zircon U-Pb dating of sericite quartz phyllite(D1016) was carried out, and the magmatic crystallization age of 1497±14Ma and the metamorphic age of 893±17.3Ma, 425±15.7Ma and 321±27Ma were obtained respectively. It is considered that the original sedimentary rock series in the Tuanliangzi Formation, mainly composed of greenschist and sericite quartz phyllite, were formed in the middle of the Mesoproterozoic period, and were intruded and metamorphosed by the Qingbaikou granite during the Neoproterozoic global Greenwell orogenic process. During the Paleo-Tethys Ocean subduction, the Paleozoic arc metamorphism was experienced, and a single grain of 2310±15Ma detrital zircon was obtained. It is inferred that there should be an ancient crystalline basement of Guyuan in Yunxian area, western Yunnan. It can be concluded that Tuanliangzi Formation is an integral part of the folded basement rock series of Yangzi continental block.