Objective To study the effect of diabetes on development of long bones.Methods The diabetic model(STZ) of the rat was established.Rats were randomly divided into 3 normal groups：5-week(CON1), 10-week(CON2) and 15-week(CON3) and 3 diabetic groups：5-week(DM1), 10-week(DM2) and 15-week(DM3),10 rats each group. The change of collagen fiber depositing was observed by Van Gieson staining method. The microvascular density was measured by the ink infusion method.The techniques of in situ hybridization and RT-PCR were used in this study in order to analyze the intensity of vascular endothelial growth factor (VEGF)mRNA expression and content of decorin,respectively.Results The thickness and cellular density of the cell pillar in the growth plate were obviously lower in the 15-week diabetic group than those in the control group(EM>P/EM> <0.05).The content of collagen in the calcified zone of the growth plate was higher than that in the control group(EM>P/EM> <0.05),and the content of decorin decreased in the 15-week diabetic group(EM>P/EM> <0.01),the intensity of VEGFmRNA expression increased(EM>P/EM> <0.01),the microvascular density increased.Conclusion The cellular proliferation,differentiation and its osteogenesis mineralization in the growth plate of the femoral head in the 15-week diabetic rats a