Abstract: Objective To study the effects of supplying iodine on pituitary and thyroid function in inhabitants with iodine defeiciency.Methods The changes of serum pituitary and thyroid hormones in inhabitants with iodine deficiency were continuously tested by RIA or IRMA before and after administrating oral iodized capsule.Results Supplying iodine at early period could cause the abnormal changes of thyroid hor mones and result in thyroid disorders.At mid-period the status of high compensator y of thyr oid function caused by iodine deficiency was nearly normal.But it was in the state of compensatory again for lacking of iodine.Conclusion Although supplying iodine for the bodies with iodine deficiency could improve the status of high compensatory caused by iodine deficiency,it might result in the disor ders of pituitary and sub-clinical thyroid disease of short duration.