Severe limb amputation trauma often results in bone and soft tissue defects after debridement. Traditional replantation aims to save the limb by shortening the ischemic period and using autologous transplantation for repair, but it can lead to surgical trauma, donor site damage, and prolonged operation time. Due to contusion, pollution, and complex injury, there is no unified standard for replantation and fixation. Improper operation can easily lead to complications such as bone infection, nonunion, bone defect, and joint stiffness. This study introduces the Ilizarov technique into microsurgery to improve limb lengthening after reconstruction and standardizes the steps of replantation fixation for complex limb avulsion injuries, with a focus on clinical efficacy. A retrospective analysis was performed on 51 patients with complex limb amputation who were treated in Zhengzhou Renji Hospital from June 2009 to March 2021. On the basis of microsurgical limb replantation, Ilizarov technology was introduced to innovate the internal and external combined stepwise fixation method for replantation. Patients' gender, age, height, weight, BMI, and other general information were collected. X-ray films were reviewed regularly to observe the surgical healing of fracture, that is, the degree of limb shortening. The lengthening time, carrying time after lengthening, follow-up time, Dahl classification, Paley fracture healing classification, and Chen Zhongwei's replantation function score were used to evaluate the recovery of the affected limb. A total of 51 patients were included in this group, including 36 male patients and 15 female patients. All the amputated wounds were single limb amputation. In this group of patients, the hind limbs were shortened by 2-12.5 cm (5.32 ± 2.24) after replantation. A total of 44 patients whose hind limbs were shortened by more than 2.5 cm were treated with two-stage Ilizarov lengthening for 1.5-5.5 months (3.19 ± 1.03). The carrying time was 3-7.5 months (4.25 ± 0.94), and the follow-up time was 1-7.8 years (3.76 ± 1.69). Among the 49 survived patients, the Dahl grade of external fixation was less than Grade 2 in 89.8%. The excellent and good rate of Paley fracture healing classification was 89.8%. The excellent and good rate of Chen Zhongwei's limb replantation function classification was 79.6%. Microsurgery combined with Ilizarov technique in the treatment of limb amputation injury, limb salvage reconstruction with internal and external combined step-by-step combined fixation, and one-stage shortening and two-stage limb lengthening can reduce the occurrence of osteomyelitis, bone defect and nonunion, expand the indications of limb replantation, improve the success rate of limb replantation, with satisfactory results, and facilitate the promotion of clinical techniques.