Objective To explore the effect of multivariate health education based on Knowledge-Attitude-Practice (KAP) theory on oral health status in adolescent patients with removable appliances. Methods From September 2024 to September 2025, a total of 90 adolescent patients who were newly diagnosed at the Orthodontic Clinic of the Afffliated Stomatological Hospital of Anhui Medical University and were scheduled to receive removable molar distalization appliances were selected as the research subjects. According to the random number table method, they were divided into the control group and the experimental group, with 45 patients in each group. The control group received conventional health education, and the experimental group received multivariate health education based on KAP theory. The oral health status, dental arch morphological parameters and periodontal index were compared between the two groups. Results The total score of OHAT in the experimental group after intervention was lower than that in the control group (P<0.05). After intervention, the TM, PMD, PMBAW and BAL in the experimental group were better than those in the control group (P<0.05). After intervention, the PLI and GI in the experimental group were better than those in the control group (P<0.05). Conclusion Multivariate health education based on KAP theory can systematically improve the oral health status of adolescent patients with removable appliances, further optimize dental arch morphological parameters and periodontal index, and has deffnite clinical application value.