Archaeological studies have indicated that the red burnt clay excavated from Lingjiatan site, about 5500BP, might be the earliest ceramic material for building in China. Some tests on red burnt clay, such as the structure, firing temperature, water absorptivity and strength of pressure resistance were dose. Furthermore, some comparative tests on bricks from Han, Ming Dynasties and modern age were introduced, it was found that red burnt clay was fires from clay material over 950°C, and there were certain variational gradations from outside to inside of red burnt clay. The conclusion could be reached that strength of pressure resistance and water absorptivity for red burnt clay was similar to those of bricks of Han Dynasty and modern age, and better than those of Ming Dynasty. All of these results support strongly the archaeologist conjecture that the red burnt clay from Lingjiatan site might be the rudiment of brick.