Currently, there remain unresolved issues in the treatment of alveolar clefts, the resolution of which could greatly benefit many patients with cleft lip and palate. In alveolar cleft treatment research, a reliable tool for pre- and postoperative assessment is crucial. This study presents a concise and accurate method for postoperative evaluations of alveolar treatment, which can rapidly and accurately obtain the shape and volume of the newly formed bone. This study included helical computed tomography (CT) datasets of 20 patients who underwent alveolar bone grafting at our institute. Two observers independently measured the volume of newly formed bone in the patient’s CT images one year postoperatively, with each observer performing the measurement twice. To acquire the volume of the newly formed bone at 1 year postoperatively, the model of the newly formed bone must be constructed first. The acquisition of this model involves Boolean operations on registered preoperative and postoperative cranial 3-dimensional (3D) images. The registration of the preoperative and postoperative models is performed in MIMICS software, and the registration results can be directly confirmed layer by layer on the CT images to ensure accuracy. The mean newly formed bone ratio in this study was 39.81%±17.96%, and the mean processing time was 05:11±01:41 minutes. The intraclass correlation coefficient for bone volume measurements between the two observers was 0.999, indicating high consistency and reproducibility. This method enhances accuracy, is time-efficient, and demonstrates high reliability in evaluating postoperative bone formation.