Objective To observe the difference of bone mineral den sity(BMD )between the young and the aged people,old healthy people and old patients with hip fra cture;the incidence of hip frac-ture in the aged was also observed in order t o find out the relationship of hip fracture with osteoporosis in the aged.Met hods BMDof lumbar(L 2~4 ),femoral neck,Wards triangle and trochanteric area was measured in the healthy males(63case)and fe males(58cases)with in the age range of 20t o35years,and the BMD was evalu ated in the healthy male and female over60y ears with hip fractures.The445cases of hip fracture were reviewed from19 91to2000,of them218were males and226females with the average age o f 73.6years in males and71.9years in fe males.Results Allof quantitati ve data was analysed sta tistically.There was sig nificant difference in BMD between the young and the aged people(P