Abstract: With the waters ultrahydrogel TM 120 μm HPLC column(7.8 mm×300 mm),several experiments have been finished, including the in vitro binding assay of 153 Sm EDTMP, 153 SmCl 3 with the Cys, BSA, mouse plasma; HPLC analysis of the urine and the extracting solution of liver homogenate after having injected the 153 Sm EDTMP and 153 SmCl 3 2 h; HPLC analysis of the production ( 153 Sm EDTMP)radiation self decomposition with large dose. For the HPLC analysis, the condition is the mobile phase of 0.85 mol/mL PBS (pH=7.5), flow rate of 0.5 mL/min, sampling of 15 μL. The results are following: (1) The 153 SmCl 3 not only is able to bind with the mouse plasma in vitro, but also is able to be absorbed by liver in vivo; (2) 153 Sm EDTMP is not bind with the mouse plasma, the Cys and BSA in vitro & vivo; 153 Sm EDTMP is not found in the extracted solution of liver homogenate at n (EDTMP)∶ n (Sm)≥5∶1; 153 Sm EDTMP is not decomposed in the urine, 153 Sm EDTMP is stable in vivo; (3) 153 Sm EDTMP radiation self decomposition is not detected with large dose in the term of validity (6 d), but two small degradation peaks have been found in the production solution after 60 d, the radiochemistry purity of production is always great than 98 % during the period.