Objective To observe the effect of 99Tc-MDP in the treatment of metastasis bone disease pain with malignancies,and the influence of 99Tc-MDP to human body's Hb,WBC,PLT,serum calcium,and PS grade.Methods 99Tc-MDP was used for the treatment of bone metastases in 78 cases with malignancies:established the intravenous access,mairdined with the 99Tc-MDP,200mg,the diluted physiological brine,and in tWO hours,once a day for five days.After the rest of twenty one to twenty-eight days,the second cycle Was repeated,and each patient at least three cycles.Results 99Tc-MDP had no influence to the Hb,WBC and PLT in pre-treatment and post-treatment,but had obvious effeet on the serum calcium,the hypocalcaemia reduced obviously(P＜0.01).There was significant difference in ameliorating ache during the periods of pretreatment and post-treatment(P＜0.05).However,there was no marked improvement in PS,and no statistic difference(P＞0.05).Conclusion 99Tc-MDP has deftnite curative effect in the treatment of metastasis bone cancer,can ameliorate the ache induced by it,and can reduce the hypoealcaemia.There is no marrow inhibition and enteron reaction in the application.