Abstract: We investigate a lot of tests and select a better condition of producing ~(131)I capsules. The experiments done are expansible tests of capsules from different producers, dispensing of solidifying agent, solidifying time, ~(131)I released during solidifying, radioactive concentrations affected by the quantities of glucose and ascorbic acid under different conditions, absorbility of the solidifying agent, nuclidic purity evaluation of the products and radiochemical analysis., ~(131)I capsules produced meet requirements of the international pharmacopeia. They are convenient and safe in use.