The eyes are an important window to obtain information from the outside world, 85% of the information is obtained through the eyes, myopia accounts for the first of the eye diseases affecting vision, China is a large country of myopia, there are about 400 million myopia patients, and is further increasing. In recent years, the incidence of myopia has a tendency to be younger, and the prevalence of myopia among children is increasing year by year. According to statistics, the prevalence of myopia in Shanghai is about 30% for elementary school students and 60% for secondary school students. Myopia has become the most common eye disease affecting the health of the nation, and myopia is not only poor vision, but can also cause serious complications such as retinal detachment and glaucoma, leading to blindness. The causes of myopia include genetic and environmental factors, and most of myopia is caused by environmental factors, i.e. excessive eye use and poor eye hygiene. Excessive eye use is an important factor in the increasing incidence of myopia among adolescents. Long study hours, long duration and short sleep hours (two long and one short), more extracurricular homework, more exams and less time for extracurricular activities (two more and one less) increase the burden on the eyes. Watching TV and playing computer games add to the burden on the eyes. Especially during summer and winter vacations, children can watch TV and play computers without any control because there is no parental control, making summer and winter vacations a high incidence of myopia. Poor eye habits include reading too close to the eyes, reading in turbulent carriages, reading while walking, reading in direct sunlight or dim light, and reading while lying in bed, which further promote the occurrence of myopia. Children’s eyes are still in the developmental stage and are easily changed by the external environment. Excessive eye use and poor eye habits can easily contribute to the development of myopia. Therefore, the prevention of myopia should focus on prevention, mainly on improving the visual environment, developing good reading and writing habits and posture, and avoiding excessive use of the eyes. Reading and writing environment lighting should be appropriate, light should not be too dark or too bright. The main focus of prevention is on improving the visual environment, developing good reading and writing habits and posture, and avoiding excessive eye use. The main treatment for myopia in children is glasses, parents should not believe in certain instruments and drugs. Some parents believe that “myopia is best not to wear glasses, the more wear will be deeper”, which is not scientific, more than 100 degrees of myopia is generally advocated with glasses, if not with glasses, because the class can not see clearly not only affect learning, and easy fatigue, but will contribute to the development of myopia. The key to accurate optometry is that children’s optometry requires dilated pupils, which are performed under ciliary muscle paralysis to control regulation and exclude pseudomyopia. ok lenses (keratoplasty) and RGP (rigid gas permeable contact lenses) have the effect of slowing down the development of myopia and can be considered for children with rapid myopia development. Progressive multifocal spectacles also have a slowing effect on myopia development, but only in children with internal obliquity, which is only a small percentage of the population. For children with exotropia, they can be harmful. In conclusion, children are the age of myopia, and myopia prevention is important, and myopia prevention should start from children.