Abstract： Objective： To observe the clinical effect of iontophoresis of Jiayu Prescription I on benign simple thyroid nodules. Methods：A total of 60 patients with benign simple thyroid nodules were selected from June 2018 to December 2019. Patients were treated with iontophoresis by external application of Jiayu Prescription I at their necks for two months. The changes of Chinese medicine symptoms and thyroid nodules before and after treatment were compared. Results： Compared with that before treatment， the diameter of thyroid nodules was decreased obviously after treatment， the difference being significant(P＜0.05). Compared with those before treatment， the scores of clinical Chinese medicine symptoms of neck discomfort，sensation of foreign body in throat，distention and fullness in the chest and rib as well as fatigue were improved， differences being significant(P＜0.01). Conclusion： The iontophoresis of Jiayu Prescription I for benign simple thyroid nodules can shrink the thyroid nodules and improve the clinical symptoms.