This study is a multicenter, randomized, double-blind comparative study to valuating the efficacy and safety of QL1206 and Prolia® in postmenopausal women with osteoporosis at high risk of fracture.

Inclusion Criteria:

• Subjects who agree to participate in the study and sign the informed consent form.
• Postmenopausal women who can walk freely, aged 50-85 years (including 50 and 85 years old).
• Subjects whose absolute value of bone mineral density (BMD) in the lumbar or total hip area meets T values ≤ -2.5 and > -4.0.
• Subjects who must have at least one of the following risk factors: History of previous fragility fractures (occurring after the age of 40); history of hip fractures in fathers or mothers; increased bone turnover rate during screening; low body weight (BMI ≤ 19 kg/m2); advanced age (aged ≥ 65 years); current smoke.
• The duration of spontaneous amenorrhea was >2 years or >2 years after bilateral oophorectomy. If the status of bilateral oophorectomy is unknown or if the ovaries are preserved after hysterectomy, follicle stimulating hormone (FSH) levels >40mIU/mL may be used to confirm the status of postoperative menopause.

Exclusion Criteria:

• Bone/metabolic disease.
• Hyperparathyroidism or hypoparathyroidism.
• Thyroid condition: Hyperthyroidism or hypothyroidism.
• Rheumatoid arthritis.
• Malabsorption syndrome.
• Renal disease - severe impairment of kidney function.
• Vitamin D defViciency (25-hydroxyvitamin D, 25OHD <20 ng/mL).
• Oral or dental diseases: previous or current evidence of mandibular osteomyelitis or osteonecrosis; Acute dental or mandibular disease requiring oral surgery; Planning invasive dental surgery; Failure to recover from dental or oral surgery.
• Previously used denosumab drugs.
• Use of intravenous bisphosphonates, fluoride, or strontium to treat osteoporosis within the last 5 years.
• OOral bisphosphonates (used for at least 3 years, or used for less than 3 years but more than 3 months, with the last use occurring <1 year before the ICF).
• Use of any of the following drugs within 6 weeks prior to screening that may affect bone metabolism.
• History of more than two vertebral fractures.
• Malignant tumors.