Overview Caries is an infectious disease of chronic progressive destruction, mainly affected by a variety of factors of bacteria, if it cannot be treated timely, it gradually develops into a series of complications, such as endodontic disease and periapical disease, which affects the whole body health and reduces the quality of life of patients. The report of the fourth national oral health epidemiological survey shows that the caries rate of 12-year-old children's permanent teeth is 34.5% and the caries rate of 5-year-old children's milk teeth is 70.9%, which are 7.8 and 5.8 percentage points higher than the caries rate of the third national oral abortion respectively, and the caries rate is on the rise and the pattern is still serious. It is important to strengthen the oral health education, improve the caries prevention awareness of the public, and improve the caries prevention ability of dental hard tissues through certain measures to reduce the incidence of caries. In the past 30 years, the topical application of fluoride containing drugs and fluoride toothpaste has greatly reduced the prevalence of dental caries. However, the widespread application of fluoride has also increased the incidence of dental fluorosis and fluorosis bone disease. Laser caries prevention has good safety and convenient operation compared with other methods, and this paper will review the research on laser in caries prevention in recent years.