To study the clinical effect of one-appointment root canal therapy combined with orthodontic correction in dental pulp disease. Methods A total of 200 patients with dental pulp disease admitted to Shangnan County Heshimei Dental Clinic from January 2021 to January 2022 were selected as the research objects. They were divided into control group and observation group by random number table method, with 100 patients in each group. The control group was treated with multiple root canal therapy, and the observation group was treated with one-appointment root canal therapy. After root canal therapy, orthodontic correction and repair were carried out. The clinical efficacy, oral health, pain score and complications were compared between the two groups. Results The total effective rate of the observation group was higher than that of the control group, and the difference was statistically significant (P <0.05). The OHIP-14 score and VAS score of the observation group were lower than those of the control group, and the differences were statistically significant (P <0.05). The incidence of complications in the observation group was 1.00%, which was lower than 16.00% in the control group, and the difference was statistically significant (P <0.05). Conclusion One-appointment root canal therapy combined with orthodontic correction is effective in the treatment of dental pulp disease, which can reduce pain, improve oral health and reduce the incidence of complications.