Congenital heart disease is thought to be closely related to thyroid hormones. Surgery for congenital heart disease with cardiopulmonary bypass can lead to a significant decrease in thyroid hormones，and hypothyroidism can also affect recovery from heart surgery. Postoperative thyroid hormone replacement therapy as a feasible method，but it does not provide clear evidence of the value of thyroid hormone therapy. The routine application of thyroid hormone after cardiac surgery to correct Euthyroid sick syndrome（ESS）in children has not been established. This paper discusses the relationship between congenital heart disease and hypothyroidism to explore the feasibility of thyroid hormone replacement therapy.