Objective To explore the clinical application effect of costal cartilage in the repair of cleft lip nasal deformity and its influence on the height of apex nasi to basis nasi and the width of affected basis nasi. Methods A total of 62 patients with cleft lip nasal deformity admitted to our hospital from January 2023 to January 2024 were randomly divided into routine group and experimental group, with 31 patients in each group. The conventional group was repaired with nasal septum cartilage, and the experimental group was repaired with costal cartilage. The repair effect, the height from apex nasi to basis nasi, the width of affected basis nasiand the treatment satisfaction were compared between the two groups. Results After treatment, the repair effect of apex nasi shape, nasal columella height and nasal dorsum shape in the experimental group was better than that in the conventional group, and the difference was statistically significant (P <0.05). The height of apex nasi to basis nasi and the width of affected basis nasi in the experimental group were better than those in the conventional group, and the differences were statistically significant (P <0.05). The treatment satisfaction of the experimental group (96.77%) was higher than that of the conventional group (80.65%), and the difference was statistically significant (P <0.05). Conclusion The application of costal cartilage in the repair of cleft lip nasal deformity is helpful to improve the therapeutic effect, improve the height of apex nasi to basis nasi and the width of affected basis nasi, and improve the satisfaction of patients and their families. It is worthy of application.