Abstract: To compare the therapeutic efficacy of radionuclide therapy with 153 Sm-EDTMP and chemotherapy with pamidronate disodium (PD) in the patients with painful metastatic bone cancer, eighteen patients histogically confirmed malignancy with multifocal bone metastases are randomized into the group 153Sm(9 patients treated with 153Sm-EDTMP) and the group PD (9 patients treated with PD) prior to study. The pain score in each patient prior to therapy is more than 6 according to scoring standardization bone pain situation and therapeutic response is classified as 4 grade (inefficient, better, effective and excellent relief). The results show that 7 of 9 patients ettective, 2 cases better, and the therapeutic effective rate is 77. 8% in the group 153Sm; 4 cases inefficient, 1 case better, 3 cases effective and 1 case excellent relief, and the therapeutic effective rate is 44. 4% in the group PD. No hematological toxicity is noted. The results revealed that the therapeutic effective rate of 153Sm-EDTMP is similar to that of pamidronate disodium (P = 0. 334 8), with pain relief maintaining more than 3 weeks, but its incidence of slightly side effect of blood toxicity is more significant than that of pamidronate disodium.