Objective To analyze the repair methods of bone defects caused by the harmful removal of lower extremity long bone segmental bone fibrous structure,and to provide reference for clinical treatment.Methods Six cases of patient with adverse fibrous structure,3 cases with the jnjury of backbone of the tibia and 3 cases of femoralshaft damage were conducted as the research objects.Bone defect length after tumor resection was (17.3 ±4.2)cm,inorder to coinside with the peroneal vessels in the other side,fibulas with peroneal vessels from both sides should be cutdown.Dual fibula medial periosteal was stripped from the central longitudinal incision to the bone crest,folding fibulatwo -stage to make the front sides face to face,and then fixed the ends.The peroneal vascular was looped on one sideof graft to form a U shape.The vessels out of damage region was dissected,and was inserted fibula between the ends offracture,as the case wire or screws may be used.The peroneal vessels had to coinside with those in damage region,andimaging assessment should be taken to evaluate the healing of bone joints after surgery,at the same time,assessingpostoperative function by functional scores of Bone Cancer Society of the United States was also neccessary,finallyvascular anastomosis through the bleeding condition of the grafts were detected.Results All patients were followedup for 5 -8 years,the bone healed 1 year later,and the transplanted bone marrow cavity got recanalization 5 years later,at the same time,there was no tumorigenesis in the double fibula,and x -ray showed the good healing.All bonesturned to be normal ones without nonunion,infection and other complications.Final follow -up score of lower limbswas 91.2%.Conclusion It is effective and feasible to use a combination of double fibula to repair lower extremitylong bone defects caused by large bone fibrous dysplasia in the periosteum.