Solid tumors frequently metastasize to bone. Two bisphosphonates have been investigated for bone metastases including pamidronate disodium and zoledronic acid.By searching the PubMed, Embase, Wanfang, and China National Knowledge Infrastructure (CNKI) databases, we conducted a meta-analysis to determine the efficacy and safety of zoledronic acid compared with pamidronate disodium in reducing pain in patients with bone metastases.Studies were pooled, and the relative risk (RR) and its corresponding 95 % confidence interval (CI) were calculated. Version 12.0 STATA software was used for statistical analysis. Twenty relevant articles were included for this meta-analysis study.The complete response rate in cancer patients treatment with zoledronic acid was significantly higher than that with pamidronate disodium (relative risk [RR] = 1.32 [95% confidence interval (CI), 1.00-1.75]; P = 0.987, I = 0%). However, there was no significant difference in the rate of partial response rate (RR = 1.04, 95% CI: 0.90-1.20; P = 0.942, I = 0%) and in the total effective rate (RR = 1.06, 95% CI: 1.00-1.12; P = 0.998, I = 0%). For adverse events (AE), the incidence of headache in cancer patients with zoledronic acid was significantly lower than that with pamidronate disodium (RR = 0.82, 95% CI: 0.70-0.96; P = 0.793, I = 0%). There was no significant difference in nausea or vomiting (RR = 1.00, 95% CI: 0.92-1.09; P = 0.494, I = 0%), fever (RR = 0.98, 95% CI: 0.85-1.14; P =0.633, I = 0%), fatigue (RR = 1.01, 95% CI: 0.91-1.11; P = 0.914, I = 0%) and anorexia (RR = 1.31, 95% CI: 0.91-1.87; P = 0.024, I = 64.4%).In conclusion, this meta-analysis indicates that treatment with zoledronic acid was more effective than pamidronate disodium in the complete response assessments and the incidence of headache, an AE, was significantly lower in cancer patients with zoledronic acid.