To determine relationship between serum estradiol (E2) levels and bone mineral density (BMD)in different stages of menopausal period. The 300 healthy postmenopausal women selecting from family registration number of Ulanbatorcity randomly were enrolled for this cross-sectional study design. The women were allocated to one of four groups according to the Stage of Reproductive Aging Workshop (STRAW) classification of WHO of the forearm and tibia bone, as measured by bone ultrasound Mini-Omni. Serumestradiol levels, age and menopause were compared between the groups. Statistical analysis were performed by using SPSS 20, using ANOVA, Pearson correlation, multiple liner regression analysis. The menopausal mean age was 48.4±3.4. The mean serum estradiol levels decreasing each groups. Osteoporotic and osteopenia BMD were comparable. The mean BMD was 3785±273.4m/s for premenopausal and 3728±184 m/s postmenopausal late stage of women. The mean BMD decreasing at time since menopause, had a predictive value for postmenopausal late stage group than did serum E2 levels (p<0.05). SOS was significantly different in every stage of menopausal women (p<0.05). SOS was negatively correlated with age (r=-0.30, p<0.05). CONCLUSIONWe identified in our study the mean age of menopause was 48.4±3.4 years. We compared with average age of onset of menopause among Mongolian women and others surveys thatstudied in Asian countries it was similar. In our result of the study, decreasing estradiol level was determined from postmenopausal period and it is similar with results of researchers D.Batnaran (2010) and also other foreign researchers. When we show that our results of osteoporosis were 11.2%, osteopenia was 34.6% were similar to results of Asian women from reports of WHO in 2008 years. Osteoporosis is increasing in earlier period of postmenopausal than premenopausal stage of menopause. BMI had statistical correlation with osteoporosis