Abstract: A widely accepted therapy was ¹³¹I for patients with thyroid disease. However, the patients who had received ¹³¹I therapy may turn into a "radiant source", the individuals surrounding the patients undergone such treatment could unavoidably exposed to the radiation. The progression on the regulation or standard which relevant international organizations and departments of various countries, and the measurement and calculation of the ¹³¹I radiation dose, was used to guide the clinical practice work and determined to give the treatment of whether inpatients or outpatients, made the individuals avoid accepting unnecessary radiation exposure in the article.