Abstract: Objective To explore the influence of low-dose sex hormone on bone mass loss for postmenopausal women.Methods A total of 85 postmenopausal women were randomly divided into group A,group B and group C.Group A (n =30)was given 1.0 mg estradiol valerate (E2V) and 2.0 mg medroxyprogesterone (MPA)every day.Group B (n =30)was conducted 0.45 mg conjugated estradiol (ethinylestradiol-3-cyclopentylether,CEE)and 2.0 mg MPA every day and group C (control group,n =25)was given vitamin (VitD)200 IU every day.The administration of drugs for each group was 12 months.In addition,400 mg elemental calcium was given daily to all women in the three groups.Bone mineral density (BMD)from the second to the fourth lumbar ver-tebra (L2-4),metabolic bone biochemical markers,urine N-telopeptide /creatinine (NTX /Cr)and incidence of bone fracture were observed before and after drug administration.Results After treat-ment of 12 months,BMD of L2 to L4 increased significantly in group B while it did not increased significantly in groups A and group C.After treatment for 6 months,urine NTX /Cr reduced in the 3 groups,in which the decreased range in group B was the most significant.The difference was sta-tistically significant in NTX /Cr value of group B and group C and there were no significant differ-ence in other groups.Conclusion Domestic E2V for 1 mg combined with 2 mg MPA every day can effectively prevent postmenopausal bone mass loss,and daily administration of CEE for 0.45 mg and MPA for 2 mg is favorable for most postmenopausal women.