Objective To investigate the application of three-dimensional (3D) reconstruction technology in preoperative planning for anterolateral thigh flap transplantation. Methods A retrospective analysis was performed on the clinical data of 11 patients with skin and soft tissue defects of the extremities treated with free anterolateral thigh flap transplantation between January 2022 and January 2024, who met the selection criteria. There were 8 males and 3 females, aged 34-70 years (mean, 50.8 years). Causes of injury included traffic accidents (4 cases), machine trauma (3 cases), heavy object crush injury (3 cases), and tumor (1 case). The time from injury to flap coverage ranged from 7 to 35 days (mean, 23 days). Preoperatively, the patients’ CT angiography images were imported into Mimics21.0 software. Through the software’s segmentation, editing, and reconstruction functions, 3D visualization and measurement of the vascular pedicle, perforators, wound size, and morphology were performed to plan the flap harvest area, contour, vascular pedicle length, and anastomosis site, guiding the implementation of flap transplantation. Results The length of the vascular pedicle needed by the recipient site was (9.1±0.9) cm, and the maximum length of vascular pedicle in the donor area was (10.6±0.6) cm, with a significant difference (t=4.230, P<0.001). The operation time ranged from 220 to 600 minutes (mean, 361.9 minutes). One patient had poor wound healing at the recipient site, which healed after dressing changes. All 11 flaps survived well without necrosis. All patients were followed up 6-19 months (mean, 11 months). Four flaps showed bulkiness and underwent secondary debulking; the remaining flaps had good contour and soft texture. The donor sites healed well, with no sensory disturbance around the incision or complications such as walking impairment. ConclusionPreoperative planning using CT angiography data and 3D reconstruction software can effectively determine the flap area, contour, required vascular pedicle length, anastomosis site, and whether vascular grafting is needed, thereby guiding the successful execution of anterolateral thigh flap transplantation.