OBJECTIVErnTo investigate the effects of four different materials as carriers of bone morphogenetic protein (BMP) to repair long bone defect.rnMETHODSrn12 mm radius bone defects were made. They were divided into 4 groups in random and repaired respectively with the vascular muscle flap combined with FS/BMP (group A), vascular muscle flap/BMP (group B), bloodless muscle flap/BMP (group C) and autolyzed antigen-extracted allogeneic bone (AAA)/BMP (group D).Their abilities of bone forming to repair bone defects were observed.rn