Objective: To explore the effectiveness of the comprehensive intervention on prevention of deciduous primary caries in 3-year-old children, so as so provide reference for the prevention, health care and treatment of oral caries. Methods: Three-year-old children selected by drawing lots from 10 public kindergartens in 5 districts of Bengbu were examined in 2021, and were randomly divided into intervention group ( n =300) and control group ( n =300). During the initial examination, caries loss (dmf) including dental caries, missing teeth, filling teeth were assessed in the two groups. At the initial examination, the intervention group received caries intervention while no intervention was administered in the non-intervention group until half a year later. Intervention measures included education, diet, self-cleaning and fluoride application intervention. The number of cases and the mean of caries loss in the two groups were compared by χ 2 test. Results: Before the intervention, 43 children in the control group suffered from caries, with 88 dmf, including 44 dmf for boys and 44 dmf for girls. There were 45 children in the intervention group, with 101 dmf, including 49 dmf for boys and 52 dmf for girls. There was no significant difference in the number of dmf between the intervention group and the control group ( χ 2=0.91, P >0.05), and there was no significant difference in the prevalence rate (15.0%, 14.3%, χ 2=0.05, P >0.05). After the intervention, there were 26 new dental caries and 43 dmf in intervention group, including 25 dmf for boys and 18 dmf for girls. In the control group, there were 83 new dental caries and 168 dmf, including 72 dmf for boys and 96 dmf for girls. Compared with the control group, the new dmf in the intervention group was significantly different ( χ 2=75.38, P < 0.05). The number of new dental caries patients in the intervention group was significantly different from that in the control group ( χ 2=36.42, P <0.05). Conclusion Comprehensive interventions to prevent dental caries can significantly reduce the incidence of primary teeth caries in children. It is suggested to intervene dental caries as early as possible to reduce the incidence of dental caries and other oral diseases.