This study aimed to assess the effect of age on the regional blood flow of neck of femur in normal Chinese. 133Xe washout method was adopted. The result showed that the femur regional blood flow of normal Chinese decreased slowly with the increase of their age. The relation between age and femur blood flow might be expressed as F = -0.042Y + 9.01(F refers to blood flow, Y refers to age). The average femur regional blood flow of normal Chinese was 7.37 +/- 0.62 ml.(100 g.min)-1 for 21-40 years old. The authors suggest this result can be considered to stand for regional femur blood flow of young healthy adults.