Objective This study analyzed the alveolar changes of complete unilateral cleft lip (UCCL) patients after presurgical nasoalveolar molding (PNAM) treatment using a three-dimensional method.Methods Palate impressions of thirty UCCL patients who underwent PNAM treatment in the Affiliated Stomatology Hospital of Guangxi Medical University were taken pre-and post-PNAM. The plaster impressions were scanned using cone beam computed tomography (CBCT). The DICOM files were exported and 3D models reconstructed in Mimics 15.0. The following parameters were analyzed in SPSS 17.0: cleft alveolar gap width, alveolar arch end width, upper lip frenulum-median plane distance, alveolar shift distance, and length of alveolar section.Results After PNAM treatment, the cleft alveolar gap width and upper lip frenulum-median plane distance decreased significantly (P0.05). Alveolar shift distances for both sides increased significantly (PConclusion The impression-CBCT method supply accurate three-dimensional data of the alveolar process. The PNAM treatment can significantly correct alveolar deformity and improve appearance.