Cataract is the main cause of blindness worldwide. The normal crystalline lens is a transparent biconvex disc,with highest protein content in all human tissues. The lens is composed of capsule, lens epithelial cells, lens fiber and zonular ligment. Cataract is a decrease in the transparency of the lens, which is characterized by opacity. In recent years, with the rapid development of molecular biology, epigenetics, immunology and organic chemistry,researchers have conducted a large number of studies on the molecular basis of genetic or targeted therapy of cataract. It is important to know the molecular pathology of cataract, which is the basis of precise diagnosis and treatment of cataract.