Objective:To analyze the correlation between oral health behaviors and the incidence of dental caries two years later in infants and toddlers.Methods:It was a retrospective cohort study. Based on the Beijing Stomatological Public Project Network data system, 1 663 children were recruited to participate in 0-3 years project in 2021 and 3-6 years fluoridated foam project in 2023. In 2021, the children were 2 years old, the parents answered 11 questions related to dental caries in the children. The children with four or more caries-inducing factors were classified as having a "high risk" of developing dental caries, otherwise, they were classified as "low risk". In 2023, the children were 4 years old, and their caries status was checked by the dentists. The correlation between different caries risk levels at the age of 2 and caries status at the age of 4 in the children was compared.Results:Infants who often fell asleep with milk, drank night milk at night, and rarely gargle or drink water after eating had a relatively high caries rate and caries after 2 years, and the difference was statistically significant (all, P<0.05). Infants whose parents did not brush their teeth every day, did not floss, and ate sweets or snacks twice or more a day had a relatively high caries rate and caries after 2 years, and the difference was statistically significant (all, P<0.001). The caries risk of 1 174 (70.6%) 2-year-old children was rated as "dangerous", and that of 489 (29.6%) 2-year-old children was rated as "safe". After 2 years, the incidence of dental caries in "dangerous" group was higher than that in the "safe" group (52.7% vs 41.5%, χ2=17.36, P<0.001), and the DMFT index in "dangerous" group was also higher than that in the "safe" group (1(0, 4)比0(0, 2), H=-4.789, P<0.001). Conclusions:Oral health behavior is closely related to the incidence of dental caries caries 2 years later in infants and toddlers, and questionnaire-based caries risk assessment is feasible.