Objective:To explore the application value of digital technology in free transfer of ALTPF to repair large-area soft tissue defect of limbs.Methods:A total of 13 patients with large-area soft tissue defects of limbs treated from April 2017 to April 2020 were selected in the study, including 9 males and 4 females, aged 39-58 years old. The average age was (42.75±1.94) years old. The area of flap was 16 cm×10 cm-27 cm×18 cm. Before operation, CTA was performed on the donor and recipient areas, and the 3-dimensional image of arterial blood supply in the donor area was obtained by 3-dimensional digital reconstruction technology of CT angiography, so as to clarify the origin, course, classification, length vascular pedicle, of diameter and location of perforating fulcrum of the blood supply of ALTPF. According to the image parameters 3-dimensional, of the defect of the recipient area was reconstructed and designed with Mimics software, and the 3-dimensional digital designed flap was used accurately and standardized during the operation.Results:All the 13 flaps survived without a vascular crisis. The patients entered the follow-up for 6 to 24(mean 16) months by outpatient clinic visits combined with WeChat reviews. At the last follow-up, the surviving flaps had soft texture and good blood supply, the shape and colour of the flap were basically the same as those of normal skin. The limb function recovered well. According to Chinese Medical Association Upper Limb Function Evaluation (TAM) method and Maryland ankle function evaluation method: 8 cases were in excellent, 3 cases were in good and 2 cases were in fair.Conclusion:The preoperative application of digital technology to assist the reconstruction of large-area soft tissue defects of limbs with free ALTPF has high accuracy and standardisation. It improves the quality and success rate of free flap repair. This method is reliable, practical and with clinical value.