Objective To explore the effect of health education based on the theory of planned behavior on treatment compliance in patients with facial acne scar undergoing fractional CO2 laser therapy. Methods A total of 120 patients with facial acne scar who received fractional CO2 laser therapy in the Medical Aesthetic Center of Hunan Prevention and Treatment Institute for Occupational Disease from January 2020 to December 2023 were selected. According to the random number table method, they were divided into the reference group and the observation group, with 60 patients in each group. The reference group received conventional health education, and the observation group received health education based on the theory of planned behavior. The treatment compliance, theory of planned behavior-related variables, scar improvement, satisfaction and adverse reactions were compared between the two groups. Results The total score of treatment compliance, the scores of each dimension, the classification of good compliance, the improvement rate of scar, the total effective rate and satisfaction in the observation group were higher than those in the reference group (P<0.05). After surgery, the scores of all theory of planned behavior-related variables in the two groups were higher than those before intervention, and those in the observation group were higher than those in the reference group (P<0.05). The incidence of adverse reactions in the observation group (8.33%) was lower than that in the reference group (28.33%) (P<0.05). Conclusion Health education based on the theory of planned behavior can effectively improve the treatment compliance of patients with facial acne scar undergoing fractional CO2 laser therapy, optimize patients' behavioral attitude, subjective norm and perceived behavioral control, ameliorate scar conditions, enhance patient satisfaction and clinical efffcacy, as well as reduce the incidence of adverse reactions.