The purpose of this study is to evaluate the efficacy and safety of QLG2128 in the treatment of postmenopausal women with osteoporosis and at high risk of fracture.

Inclusion Criteria:

• Postmenopausal women who can walk freely (≥50 and ≤85 years);
• The patient has a body mass index(BMI) of 17.0 kg/m2 to 30 kg/m2；
• The patient has a bone mineral density T-score≤-2.5 and > -5.0 at the lumbar spine (L1-L4) or femoral neck or total hip by dual energy x-ray absorptiometry (DXA)；
• The patient has at least one of the following high risk factors of fracture: 1) history of previous fragility fractures; 2) family history of hip fragility fracture; 3) age≥70 years; 4) BMI≤19.0 kg/m2；5) Currently smoking.
• The patient with at least 2 consecutive vertebrae(L1 to L4) and at least 1 hip can be evaluated for BMD.

Exclusion Criteria:

• In addition to postmenopausal osteoporosis, the other diseases affecting bone metabolism；
• History of osteosarcoma；
• History of orthostatic hypotension；
• Currently suffering from active urinary calculus；
• Received anti-osteoporosis treatment that does not meet protocol requirements；
• Received medication that affects bone metabolism within 4 weeks prior to screening, or is planned to use prohibited drugs/non-drug therapy under the protocol during the study period.