Objective To assess the efficacy and safety of parathyroid hormone (PTH) on bone mineral density (BMD) and fractures in postmenopausal women with osteoporosis. Methods We searched MEDLINE (1966 to March 2008), EMBASE (1974 to March 2008), The Cochrane Library (Issue 1, 2008), Current Controlled Trials, The National Research Register, CBM (1983 to March 2008) and CNKI (1994 to March 2008). Some related journals were hand searched as well. The quality of included randomized controlled trials (RCTs) was evaluated and meta-analysis was conducted by The Cochrane Collaboration’s software RevMan 4.2.10. Results Twelve studies involving 5550 patients were included. PTH alone or in combination with antiresorptive drugs reduced the risk of vertebral fracture (RR=0.34, 95%CI 0.26 to 0.45, Plt;0.000 01), and increased spine BMD (SMD 0.41, 95%CI 0.17 to 0.65, P=0.0009) and femoral neck BMD (SMD 0.13, 95%CI 0.03 to 0.22, P=0.008). The rate of drop out and loss to follow-up because of adverse events was significantly higher in the PTH group (Peto-OR=1.69, 95%CI 1.39 to 2.05, Plt;0.000 01). Conclusion PTH is effective in the prevention and treatment of postmenopausal osteoporosis, especially in patients with preexisting osteoporotic fractures or with very low bone density. PTH alone or in combination with antiresorptive drugs can reduce the risk of vertebral fractures and increase spine and femoral neck BMD. PTH is more effective than alendronate, but these two should not be used as a combined treatment.