This study investigated the adsorption property of iodine-131 and adsorption efficiency of ruthenium-103 and zirconium-95 contained as a very small amount in α-benzoinoxime precipitation process. Iodine-131 is adsorbed by reaction with silver impregnated on activated carbon, but activated carbon is used about forty times more than stoichiometry as adsorbing iodine-131 of 0.1 mg per 1 g. Adsorption capacity increases according as increasing iodine-131 concentration and equilibrium curve is linear. Equilibrium time is eight hours and takes a ling time comparing to 105 minutes of organic's adsorption experimental result. Loss ratio of molybdenum-99 was 3.6 % and decontamination factor of iodine 131, ruthenium-103, and zirconium-95 was 432.9, 1.3, and 3.0, respectively in the adsorption process of iodine-103 and organic by silver impregnated activated carbon.