Several decades of geological investigations and specific research in southern China have greatly deepened our understanding of the Pre Devonian tectonics of Southern China as follows. ① In southeast China, the metamorphic rocks, overlain unconformably by the Devonian sediments, host graptolites, trilobites and Brachiopoda, suggesting the rocks are Neoproterozoic to early Paleozoic in age, and the metamorphic rocks in the Wuyi Yunkai area, such as the Chencai and Dikou complexes with metamorphic ages of 460~440Ma, are proved to be the products of the Caledonian orogeny rather than of the pre Sinian orogeny. Therefore, South China is not a pre Sinian Cathaysia old land, but a Caledonian orogen. The high grade metamorphic rocks in the Wuyi Yunkai area, which underwent the severest tectonism and magmatism in the South China orogen, might be the rock for the orogen. ② During the pre Devonian, Southern China was divided into three tectonic units: the South China Sea platform (Indochina South China Sea platform), the South China orogen and the Yangtze paraplatform. During the Neoproterozoic, the South China orogenic belt was characterized by volcanic and volcaniclastic rocks, and by terrigenous clastic rocks in early Paleozoic but no reliable ophiolitic suite recorded. The Nd model ages and inherited zircon ages for widespread granites in the South China orogen suggest the Archean to Proterozioc in age, illustrating that there should be an ancient continental crust beneath the orogenic belt. Lithofacies paleogeographic research shows that terrigenous clastics of lower Paleozoic rocks in South China were derived from the South China Sea platform. And biostratigraphic and tectonic studies indicate a transitional relation between the Yangtze paraplatform and the South China orogen. It can be inferred that the Yangtze paraplatform, South China orogen and South China Sea platform should belong to one continental plate, the Southern China plate. ③ The latest isotopic dating indicates that the Shuangqiaoshan, Sibao and Lengjiaxi groups are the Neoproterozoic metamorphic rocks rather than the Mesoproterozoic ones; that is to say, they resulted not from the Greville orogeny (1300~1000Ma), but from the Sibao or Wuling orogeny (820Ma). Therefore, southern China should be part of the Gandwana continent rather than part of Rodinia supercontinent.