Abstract: Objective :To evaluate the efficacy and safety of Zoledronic acid in the treatment of malignant hypercalcemia. Methods :A multicentral,open phase-II clinical trial was conducted in 15 cases with malignant hypercalcemia reciving Zoledronic acid intravenously for 15 min.The level of blood-calcium and side effects were recorded regularly within 28 days after injection. Results :The drop-out occurred in one case due to bad compliance.The complete response rate(CR)(the corrected blood calcium reached normal level)was 100.00%(14/14).The median time of CR was 5.07 days.The median sustaining time was 22.30 days.Slight or moderate fever was observed. Conclusion :Zoledronic acid can effectively reduce the malignant hypercalcemia and the use of zoledronic acid appears to be safe and convenient.