Objective To investigate the prevalence of dental caries among preschool children in Chongming District， Shanghai， and to analyze the related factors influencing dental caries in preschool children in Chongming District， in order to provide references and suggestions for the prevention of dental caries in preschool children in Chongming District.

Methods From January to April 2022， 939 preschool children from 5 kindergartens in Chongming District of Shanghai were selected as the research objects through random cluster sampling. The dental caries prevalence rate and related risk factors of dental caries in preschool children were studied through oral examinations and questionnaire surveys.

Results The prevalence rate of dental caries among the 939 preschool children was 45.69%. The prevalence of dental caries in preschool children was not related to gender but increased with age （P<0.001）. Risk factors for dental caries in children included consuming desserts between meals or before bedtime （OR=3.049， P<0.001）， consuming sugared milk （OR=2.389， P=0.027）， presence of dental caries in caregivers （OR=1.888， P<0.001）， age （OR=1.758， P<0.001）， regular consumption of certain beverages by children （OR=1.250， P=0.029）， and the frequency of snack consumption （OR=1.191， P=0.034）.

Conclusion To reduce the incidence of dental caries in preschool children， it is recommended that caregivers undergo oral health examinations and dental caries treatment to reduce the transmission of cariogenic bacteria. Additionally， reducing the frequency of children’s consumption of snacks， sugary drinks， and dairy products， and avoiding unhealthy eating habits such as consuming desserts before bedtime are advised. It is also important to educate children on proper toothbrushing methods to ensure the effectiveness of toothbrushing and to encourage them to develop good oral hygiene habits.