Abstract Summary The efficacy of generic teriparatide in improving BMD at lumbar spine in patients with osteoporosis was similar to that of alendronate. It provided a new choice for osteoporosis treatment in Chinese population. Introduction To determine whether the efficacy of generic teriparatide is noninferior to alendronate for Chinese postmenopausal women with osteoporosis. Methods Eligible patients were randomly assigned (2:1) in a 48-week, open-label design to receive 20 µg sc daily teriparatide or 70 mg oral weekly alendronate. Primary outcome was percentage change in BMD at the lumbar spine from baseline to 48 weeks and was assessed for non-inferiority. The same outcome was further assessed for superiority as a secondary endpoint. Results Three hundred ninety-one and 196 participants were randomly assigned to the teriparatide or alendronate group, of whom 379 and 194 receiving at least one dose of teriparatide and alendronate treatment were eligible for the efficacy analysis. Teriparatide was non-inferior to alendronate for BMD change at lumbar spine (treatment difference: 0.7%, 95% CI: − 0.3 to 1.7%), which excluded the predefined non-inferiority margin of − 1.5%. However, teriparatide was not statistically superior to alendronate in improving BMD at lumbar spine (P = 0.169). At 48 weeks, changes in BMD at total hip were − 1.0% and 2.2% in teriparatide and alendronate group, respectively (P < 0.001). The incidence of new fracture showed no statistical difference between groups (P = 0.128). Serum P1NP and β-CTX levels significantly increased in the teriparatide group and markedly decreased in alendronate group (all P < 0.001 vs baseline). The adverse events (AEs) and serious AEs were more common in the teriparatide group than in the alendronate group, which were mainly teriparatide-related hypercalcemia, elevated alkaline phosphatase or parathyroid hormone, dizziness, and arthralgia. Conclusions Teriparatide was not inferior to alendronate in increasing BMD at lumbar spine in Chinese postmenopausal women, and they achieved these effects through different mechanisms.