Abstract: Hypothyroidism is main complication after ¹³¹I therapy for hyperthyroidism in Graves' dis-ease. The hypothyroidism restricts its popular application that ¹³¹I treatment for Graves' disease. In clinic practice, different factors of every patient, involved case selection, sensitivity estimation, unite using medicine before ¹³¹I therapy are analysed, and synthetic measures for post treatment examination, transient hypothyroidism and permanent hypothyroidism after ¹³¹I therapy are discussed.