In this work, the structure and chemical composition of thin films of white mica found in Si-Chuan Province are studied by transmission electron microscopy and scanning electron microscopy. The. thickness is in the range of 300-1000?. It is concluded that the sample is nearly perfectly crystalline and contains no detectable impurities, however some defects are discovered in certain regions as shown in the text (Fig. 2-4).Thin mica film can be used as a substrate on which other thin film can deposit or grow into large crystalline grains.