The work was to observe the effects of γ-rays radiation of rat kidneys on rat bone metabolism. Ten male SD rats aged 6 months were irradiated at their kidneys with 15Gy ,137,Cs γ-rays( 0.91 Gy/min) and were raised for 3 months after the radiation. On collecting 24h urine of rats they were sacrificed for serum, kidney, spine , femur and tibia exams. Results show that theγ-ray irradiation could induce the pathological injuries of renal glomeruli, tubules and mesenchyme. Comparing to the control group, significant chages were found in the irradiated group in terms of their blood urea, nitrogen creatinine, urinal ,β,-2 microglobulin, serum Ca and P, urine Ca and P, activity of serum alkaline phosphatase, 1,25(OH),2, D,3, serum PTH, urine PYD/creatinine, bone mineral density(BMD) of lumbar vertebras, mineral mass of No.4 lumbar vertebra, BMD, dehydrated weight and ash weight of right femur. Marked changes were also found in bone trabecula volum, average bone trabecula thick and the ratio of nodes/points, and rate of mineralizatal deposition. It was concluded that renal dysfunction and metabolic bone disease might occur with the character of accelerated bone turnover and decreased bone mass.