Objective: To report the clinical outcome of repairing massive bone defects biologically in limbs by homeochronous using structural bone allografts with intramedullary vascularized fibular auto-grafts. Methods: From January 2001 to December 2005. large bone defects in 19 patients (11 men and 8 women, aged 6 to 35 years) were repaired by structural bone allografts with intramedullary vascularized fibular autografts in the homeochronous period. The range of the length of bone defects was 11 to 25 cm (mean 17. 6 cm), length of vascularized free fibular was 15 to 29 cm (mean 19. 2 cm), length of massive bone allografts was 11 to 24 cm (mean 17. 1 cm). Location of massive bone defects was in humerus(n = 1), in femur(n = 9) and in tibia(n = 9), respectively. Results: After 9 to 69 months (mean 38. 2 months) follow-up, wounds of donor and recipient sites were healed in Ⅰ stage, monitoring-flaps were alive, eject reaction of massive bone allografts were slight, no complications in donor limbs. Fifteen patients had the evidence of radiographic union 3 to 6 months after surgery, 3 cases united 8 months later, and the remained one case of malignant synovioma in distal femur recurred and amputated the leg 2. 5 months, post-operatively. Five patients had been removed internal fixation, complete bone unions were found one year postoperatively. None of massive bone allografts were absorbed or collapsed at last follow-up. Conclusion: The homeochronous usage of structural bone allograft with an intramedullary vascularized fibular au-tograft can biologically obtain a structure with the immediate mechanical strength of the allograft, a potential result of revascularization through the vascularized fibula, and accelerate bone union not only between fibular autograft and the host but also between massive bone allograft and the host.