Objective To investigate the application of mind mapping-based health education in extended care for children with caries. Methods This was a prospective study of 159 eligible children with caries. Participants were randomly assigned to an observation group and a control group, and received extended health education and guidance. Patients in the observation group received health education with mind mapping. In the third month after the first visit, a questionnaire survey was conducted to assess knowledge of extended caries diagnosis and treatment in children and their parents. Children also underwent a bacterial plaque test. Results Caries knowledge was significantly greater in the observation group than in the control group. There was no significant between-group difference in debris index on the bacterial plaque test. The observation group had a significantly greater number of follow-up visits in 12 months than the control group. Conclusions Mind mapping was effective in the implementation of extended care. Mind mapping information was more accessible to children and their parents, increasing their compliance with health education. Thus, mind mapping is an appropriate health education tool for use in extended care for children with caries.