Objective To explore the Ilizarov reconstructive technique and its efficacy for the complicated bone defect in long bone. Methods From January 1996 to January 2005, totally 61 patients suffered with long bone defect were observed, which involved 46 males and 15 females with an average age of 28.2 years(range, 6-55 years). The bone defect occurred on the tibia in 29 patients, femur in 9, humerus in 11, radius in 7, ulna in 5. The treatment was tailored to the different length of defect: 30 patients with defect 4-6 cm were treated with the Ilizarov osteotomy and lengthening method; 21 patients with defect 6-9 cm were treated with the segmental transporting technique; 10 patients with defect beyond 9 cm were treated with pedicle fibular graft and Ilizarov fixation. The average bone lengthening was 4.8 cm with the duration of follow up from 10 to 84 months(with an average of 47 months). Results All the 61 cases averagely got bone union at 7.1th month and fixator removal at 8th month after operation, respectively. The low-grade infection and effusion occurred in 78 pin tracts on 21 patients, which were attributed to bone absorption around the pin and improper wound care. And still 1 patient with fibular transplantation got refracture due to trauma before the fixator removal. Conclusion The key point in the Ilizarov technique for the long bone defect nonunion is to excise the lesion thoroughly, and reconstitute it later. The Ilizarov technique is an effective method to treat the severe defect in long bone and restore the extremity length.