To investigate the effectiveness of the digital technology in repairing hand soft tissue defect with the lateral arm perforator flap. Methods From January, 2015 to February, 2018, 15 cases of hand soft tissue defect were treated with free lateral arm perforator flaps transferring. Injury site: 7 cases on the back of the hand, 4 cases on the palm, and 4 cases on the mouth of the tiger. All of them had tendon exposure. The size of defect was 2.0 cm×1.5 cm to 14.0 cm×5.0 cm. CT angiography was conducted and analyzed before operation, and the donor sites and preferred perforators were selected.Then the CTA data was imported into the Mimics 17.0 software to recon-struct the three dimensional structure of the perforators, bone, and skin. The flap was obtained on the basis of preop-erative design during operation.The size of flaps varied from 3.0 cm×2.0 cm to 15.0 cm×6.0 cm.The survival status of the flap, the appearance and function of the hand were followed-up and analyzed after operation. Results All the flaps survived. The wounds and incisions at donor sites healed primarily. The patients were followed-up for 6-12 (mean, 8) months. The hand function recovered satisfactorily, and the sensation was S2-S3 at 6 months after operation. According to the functional assessment criteria of upper limb formulated by the Hand Surgery Branch of Chinese Medical Association, the results were excellent in 4 cases, good in 9 cases, and fair in 2 cases. The linear scars were observed at the donor sites. Conclusion The lateral arm perforator flap has a stable vessel pedicle, good texture and sensation. So it is a good method to repair soft tissue defects of hand. The preoperative individualized design of the lateral arm perforator flap can realize through CTA digital technology and Mimics 17.0 software. It can reduce the operation risk.