With the development of high technology, people spend more and more time on screens. Most screens contain a lot of blue light. As one of the important components of visible light, blue light has high energy. It may lead to many ocular diseases, such as myopia, cataract, dry eye, glaucoma and keratitis when eyes exposure to blue light for a long time. At present, the harm of blue light and how to prevent blue light have become a hot topic. Its mechanism mainly includes increasing the photosensitivity of lipofuscin, destroying the mitochondria, lysosome, lens and tear film. According to the mechanism of blue light damage, physical protective measures can be adopted. And the antioxidant, free radical scavengers, anti-inflammatory drugs and gene therapy can be used to protect eye tissue. This paper mainly summarizes the harmful mechanism of blue light to eye and the corresponding prevention and treatment measures.