Objective: Bisphosphonates were widely used with the rate of malignant tumor with bone metastases increasing rapidly. The aim of this study was to evaluate zoledronic acid and pamidronic acid on treating osteatgia of malignant tumor with bone metastases and serum calcium, phosphorus and alkaline phosphorus movement. Methods: One Hundred cancer patients with bone metastases were diagnosed according to pathological and imaging methods. After zoledronic acid or pamidronic acid intravenous infusion one and two months, ostealgia degree, serum calcium, serum phosphorus and alkaline phosphorus were observed before bisphosphonates treatment, one and two months after treatment, respectively. Results:Ostealgia degree did not change significantly after diphosphonates treatment from one to two months (P ＞ 0.05). The linear correlation between serum calcium and serum phosphorus on bone metastases cancer patients before therapy was dismissed after bisphosphonates treatment one month and did not recover in two months. The incidence of hypo-calcium after diphosphonate treatment one month (54%) and two months (56%) were significantly increased than that before treatment (36%) (x2 = 6.55, P = 0.011; x2 = 8.05, P = 0.005). Serum calcium and serum phosphorus were both decreased after treatment one month (t = 4.39, P = 0.000; t = 2.50, P = 0.014) and two months (t = 4.32, P = 0.000; t = 2.49, P = 0.010). There had no difference between zoledronic acid and pamidronic acid on treating of ostealgia and serum calcium and phosphorus changing.Conclusion: Zoledronic acid and pamidronic acid can relief ostealgia of cancer patients with bone metastases and inducehypo-calcium, break the linear relationship between calcium and phosphorus. There have no difference between zoledronic acid and pamidronic acid on treating ostealgia and inducing hypo-calcium and hypo-phosphorus.