Abstract: This approach addresses the current research in palaeoecology which focuses on the early metazoan biotas in China during the Doushantuoan （Late Sinian）. Two important categories have been classified for the Sinian biotas: Miaohe and Weng’ an biotas on the Upper Yangtze platform. Of particular significance is why and how these biotas flourished and were preserved during geological time. The author contends that abundant SiO₂ and P₂O₅ supplied by the upwelling currents permitted the living organisms to get thriving on a larger scale on the margins of the platform. The steady increase in SiO₂ and P₂O₅ resulted in intense phosphatization and silicification; that is to say, the abundant organic remains were rapidly phosphatized and silicificated, and got out of oxidization and decomposition. It can be seen that mineralization （phosphatization, silicification and manganesation） may be interpreted as an important factor in the preservation of the organic remains as fossils, and that the Upper Yangtze area is a favourable region in China for the flourishing of organisms during the Doushantuoan （Late Sinian）.