To analyze the effect of orthodontic treatment combined with one-appointment root canal therapy in patients with dental pulp disease. Methods A total of 60 patients with dental pulp disease admitted to our hospital from April 2022 to June 2023 were randomly divided into control group and observation group, with 30 patients in each group. The control group received orthodontics combined with multiple root canal therapy, and the observation group received orthodontics combined with one-appointment root canal therapy. The clinical efficacy, masticatory function, complications and quality of life were compared between the two groups. Results The total effective rate of treatment in the observation group was 96.67%, which was higher than 80.00% in the control group (P <0.05). After treatment, the masticatory efficiency and bite force of the observation group were higher than those of the control group (P <0.05). The incidence of complications in the observation group was lower than that in the control group (P <0.05). After treatment, the quality of life scores of the observation group were higher than those of the control group (P <0.05). Conclusion Orthodontic treatment combined with one-appointment root canal therapy has a good effect on dental pulp disease, which is helpful to improve the masticatory function, relieve disease-related symptoms, and reduce the inci dence of complications.