Abstract: According to middle-high grade metamorphic rock assemblages，structural defomational styles and newer data of isotopic ages, this paper suggests that a Precambrian continental block existed in the southern Zhejiang-northern Fujian-central-southern Jiangxi-eastern Guangdong region,South China．This oldland, with the oldest isotopic age of 2100 Ma and named the Cathaysian Oldland，is characterized by large scale development of schist，gneiss and migmatic rocks with the interval from l8O0Ma to 1200 Ma，which comprise the continental crustal basement About 1100- 90OMa, the Cathaysiml Oldland collided with the Yangzi continental plate to form the Shaoxing-Jiangshan-Dongxiang-Pingxiang Fault Zone．Not long time later, about 800 Ma, the Cathaysian 0ldland was dispersed into three blocks with different strikes and distinct outline，that is，the NEE striking Southeastern Zhejiang—-Northwestern Fujian Block，the sub-N-S-striking Central Jiangxi-Southern Jiangxi Block and the NE striking Yunkaidashan Block，respectively. The Sinian-Early Paleozoic sedimentary materials with a large thickness filled among these three blocks Study proposes that this oldland subjected to three-phase tectonic-thermal events at least，the Luliang event(1 800-1 600Ma)，the Jinning event(1 100—900Ma)and the Caledonian event(420—40OMa)since the Neo-Proterozoic to become the tectonic basement of the Late Mesozoic (mainly Cretaceous) volcanic-lntrusive complexes. The basement feature of the Southeastern Coasta1 Region is not clear due to 1ack of Precambrian outcropped rocks and isotopic age data．But according to the geochronological age of 1806Ma by the whole rock Rb-Sr method on the core of gneissic rock from the Linfeng hole NO．1 in East China Sea(East of Wenzhou)，we guess that a Proterozoic metamorphic block should exist under the Meso-Cenozoic sedimentary rocks of the East China Sea. During the Late Mesozoic-Paleogene，a large-scale intra-continental rift basin was formed along the Shaoxing-Jiangshan Dongxiang-Pingxiang Fault Zone, in which red bed was filled．This ancient tectonic framework constrains 1arge scale Mesozoic tectonics-magmatism and difference in magmatic compositions and distributrion.