In order to do quantitative studying on femur cortical and trabecular bone loss induced by aging in aged male rat,male SD rats aged 24 months had been fed for 6 months.Both the rats aged 24 months and the rats aged 30 months were examined in femur Bone Mineral Density(BMD) in proximal,distal segments composed of a lot of trabecular bone and middle segment composed of a lot of cortical bone.The result indicated that the femur BMD in respective segment of the rats aged 30 months was significantly lower than that of the rats aged 24 months.It revealed that the model for bone loss induced by aging in aged male rat was duplicated successfully.