Objective To analyze the application effect of orthodontic porcelain cosmetology in the repair of anterior subgingival crown fracture. Methods A total of 52 patients with anterior subgingival crown fracture who were treated in our hospital from January 2021 to October 2022 were randomly divided into control group and observation group, with 26 patients in each group. The control group was given basic post crown repair, and the observation group was given orthodontic porcelain cosmetic treatment. The clinical efficacy, occlusion degree, aesthetics, periodontal occlusion function, periodontal health and repair satisfaction were compared between the two groups. Results The total effective rate of clinical treatment in the observation group was 96.15%, which was higher than 65.38% in the control group, and the difference was statistically significant (P<0.05). The scores of occlusion and aesthetics in the observation group were higher than those in the control group, and the differences were statistically significant (P<0.05). The periodontal occlusal function and periodontal health of the observation group were better than those of the control group, and the difference was statistically significant (P<0.05). The repair satisfaction of the observation group was 96.15%, which was higher than 69.23% of the control group, and the difference was statistically significant (P<0.05). Conclusion Orthodontic porcelain cosmetology repair can improve the occlusal degree and aesthetics of patients with anterior subgingival crown fracture, promote the improvement of periodontal occlusal function, and maintain periodontal health. Meanwhile, it has definite curative effect and is more easily accepted by patients, with higher clinical application value