Objective To systematically assess the efficacy of alendronate in improving bone mineral density (BMD) in postmenopausal women. Methods The databases such as the Cochrane Library, PubMed, EMBASE, CBM, CNKI and VIP were electronically searched for all randomized controlled trials (RCTs), with deadline of September 2013, without language restrictions. Women with postmenopausal osteoporosis were included as the research objects, the RCTs on the efficacy comparison between alendronate (tablets) and placebo were collected, and the quality of clinical trials were evaluated. RevMan5.2 software was used for analysis.Meta regression models were established by using the Stata11.0 software to discuss the source of heterogeneity of primaryindex for assessment of curative effect. Results Twelve studies with 5 466 patients were included. Meta analysis on primary and secondary curative effect index showed that compared with placebo, alendronate (10mg daily/1 year, 10mg daily/2-3 years and 5mg daily/2-3 years) significantly increased BMD at the lumbar spine, total hip, trochanter and femoral neck, and the changes oflumbar BMD were in maximum (WMD=5.39, 7.70 and 5.99, 95%CI: 4.03-6.76; 6.96-8.43; 5.16-6.82; respectively), followed by the trochanter and the femoral neck, and the BMD was increased with the medication time and dosage. Conclusions Alendronate could effectively increase BMD in postmenopausal women, and we recommend that the treatment course of alendronate should be 2-3 years at least. Key words: Alendronate; Bone mineral density; Menopause