AIM:To conduct the relevance analysis of serum Dickkopf-1 (Dkk-1) and bone mineral density (BMD) in the different ages of female populations.METHODS: The women volunteers (n=100, 20~80 years old) were selected and divided into young group (20~39 years old), middle age group (40~59 years old) and elderly group (60~80 years old).The serum levels of Dkk-1 in the 3 groups of volunteers were detected by ELISA.In the middle age group, 25 people of 45~55 years old were selected and divided into postmenopausal group and premenopausal group to de-tect the serum level of Dkk-1 in the 2 groups of volunteers by ELISA.The BMD was measured by the method of dual energy X-ray absorptiometry.The differences of Dkk-1 expression levels among different ages of female populations, and the rele-vance with BMD were compared.RESULTS:With the increase in age, the serum Dkk-1 expression level increased ( P<0.05), and BMD were reduced (P<0.05).The blood level of Dkk-1 and BMD negatively correlated (P<0.05) in the 3 groups of volunteers.The serum levels of Dkk-1 and BMD had stronger negative correlation in postmenopausal women group than that in premenopausal women group.CONCLUSION:With the increase in age, the expression level of serum Dkk-1 increases and the BMD level decreases, which contribute to a risk of osteoporosis.In the same age range, the postmeno-pausal women express higher level of Dkk-1, and the decreased BMD is more obvious, which contribute to a greater risk of osteoporosis.The increased level of Dkk-1 also inhibits bone formation and promotes bone resorption.It may become a new target for preventing and treating osteoporosis.