Abstract: Objective To study the optimal cut-off value of phalangeal radiographic absorptiometry (RA) to identify osteoporosis in postmenopausal women. Methods A total of 650 postmenopausal women were recruited in this study. Bone mineral density (BMD) at lumbar spine and left proximal femur neck was measured by dual-energy X-ray absorptiometry (DXA) as the standard method to identify postmenopausal osteoprosis. Phalangeal bone density was estimated by the use of RA. Optimal cut-off value of phalangeal RA was determined using a ROC curve for screening the ostreoporosis cases. Results When the cut-off value of phalangeal RA was T score ≤-2.5, the sensitivity was 74.2%, the specificity was 72.9%. When the cut-off value was T score ≤-2.21, the sensitivity was 81.4%, the specificity was 62.0%. Conclusion The cut-off value of phalangeal RA as T score ≤-2.21. which has higher sensitivity could be optimal to identify postmenopausal osteoporosis.