Objective: To evaluate the clinical effect of WeChat applet on caries prevention of 5 year old children, and to provide reference for the application of new technology in the prevention of dental caries in children. Methods: Five year old children with high caries risk from Pediatrics Dentistry of Hefei Stomatological Hospital were randomly recruited and divided into experimental group ( n =64) and control group ( n =59) during August to October 2021. The control group received routine oral health education, while the experimental group received tooth brushing reminders and video push notifications of oral health education. Caries risk, plaque index (PLI), gingival index (GI), decayed missing filled tooth (dmft), decayed missing filled tooth surface (dmfts) as well as oral health knowledge, attitude, practice (KAP) score of guardians were compared between the two groups 6 months after intervention. Results: At six months after intervention, the percentage of children with high caries risk in the experimental group (14.06%) was significantly lower than that of the control group (67.80%)( Z =-5.85, P <0.05). The PLI in the experimental group [1(1,2)] was significantly lower than that of the control group [2(2,3)]. The dmfts of children in the experimental group (12.17±8.30)was significantly lower than that of the control group(15.18±6.24). The oral health KAP score of the guardians in the experimental group [78(74,81)] was significantly higher than that of the control group [68(63,71)]( Z/t=-6.67, -2.29, 8.94, P < 0.05 ). Conclusion The integration of WeChat applet technology into oral health education can effectively improve oral health condition of children and enhance the oral health KAP of guardians.