Objective To investigate EM>in vivo/EM> expression at early stage of three bone growth factors and osteocalcin on magnesium alloy/bone interface in New Zealand white rabbits. Methods The Ca-P coated and the naked Mg-Mn-Zn alloy rods were implanted respectivelys into the left femoral metaphysis of rabbits. Intravital staining was performed using subcutaneous injections of 1% water solution of calcein to observe the newly formed bone. Postoperatively, three rabbits were sacrificed at 1, 2, 3 and 4 weeks for X-ray examination, fluorescent observation, routine pathological examination and bone morphogenetic protein （BMP）, transforming growth factor βSUB>1/SUB>（TGF-βSUB>1/SUB>）, platelet-derived growth factor （PDGF） and bone gla protein（ BGP） immunohistochemistry. Results X-ray examination showed that both experimental and controlled rods were encircled by new bone, and HE staining and fluorescent observation showed no differences between two groups, but immunohistochemistry and associated statistical ananlysis displayed obvious differences on average absorbance values of BMP-2, TGF-β1 and PDGF expression. Average absorbance values of experimental group expressed higher than thoese of cont