Objective To explore the effect of Health Action Process Approach (HAPA) model combined with feedforward control systematic oral nursing on treatment compliance and gingival indicators in children with orthodontics. Methods A total of 80 children with orthodontics admitted to Hospital of Stomatology, Sun Yat-sen University from June 2024 to June 2025 were selected as the research subjects, and they were divided into the control group and the study group by the random number table method, with 40 children in each group. The control group received conventional nursing, and the study group received HAPA model combined with feedforward control systematic oral nursing. The treatment compliance, gingival indicators, masticatory efffciency and complication rate were compared between the two groups. Results The treatment compliance rate of the study group (97.50%) was higher than that of the control group (80.00%) (P<0.05). The PLI, SBI and GI of the study group after intervention were lower than those of the control group (P<0.05). The masticatory efffciency of the study group after intervention was higher than that of the control group (P<0.05). The incidence of complications in the study group (2.50%) was lower than that in the control group (20.00%) (P<0.05). Conclusion HAPA model combined with feedforward control systematic oral nursing can improve the treatment compliance of children with orthodontics, optimize their gingival indicators, enhance their oral masticatory ability, and reduce the risk of complications after orthodontics, which is worthy of clinical application.