Objective To systematically evaluate the effectiveness and safety of zoledronic acid combined with radiotherapy in treating bone metastasis of malignant tumor. Methods Such databases as PubMed, EMbase, The Cochrane Library (Issue 10, 2012), CBM, CNKI, VIP and WanFang Data were searched to collect randomized clinical trials (RCTs) on bone metastasis of malignant tumor from inception to October, 2012. References of included studies were also retrieved. Two reviewers independently screened studies according to exclusion and inclusion criteria, extracted data, and assessed the methodological quality. Then, meta-analysis was performed using RevMan 5.1 software. Results Twenty nine trials were included involving 2 021 patients. The results of meta-analysis showed that, compared with the radiotherapy alone group, zoledronic acid combined with radiotherapy improved the effectiveness rate of pain relieving at the end of treatment (OR=3.08, 95%CI 2.30 to 4.12, Plt;0.000 01), the effectiveness rate of pain relieving two weeks after treatment (OR=3.39, 95%CI 2.52 to 4.56, Plt;0.000 01), the quality of life (OR=2.74, 95%CI 1.66 to 4.52, Plt;0.000 01) and the ability of movement (OR=2.96, 95%CI 2.16 to 4.05, Plt;0.000 01). Zoledronic acid combined with radiotherapy also reduced the incidence of new bone metastasis (OR=0.21, 95%CI 0.10 to 0.45, Plt;0.000 1) and the incidence rate of bone-related events (OR=0.17, 95%CI 0.03 to 0.92, P=0.04). The adverse reactions of zoledronic acid combined with radiotherapy such as fever (OR=11.92, 95%CI 6.31 to 22.48, Plt;0.000 01) and hypocalcaemia (OR=8.82, 95%CI 1.61 to 48.36, P=0.01), significantly increased. Conclusion Compared with radiotherapy alone, zoledronic acid combined with radiotherapy can relieve bone metastatic pain, effectively enhance patients’ ability of movement, improve quality of life, and decrease new bone metastasis and the occurrence of bone-related events.