Hashimoto’s thyroiditis is often insidious and not easily detected, but is usually discovered by chance during physical examination. The typical clinical manifestations: mostly seen in women, in the past the middle-aged and elderly, but now also common in young women, slow onset, long course, localized thyroid gland showing diffuse enlargement, hard texture, painless or light pressure, smooth surface, may have nodules, local pressure and systemic symptoms are not obvious, occasionally pharyngeal discomfort. Hashimoto’s thyroiditis often takes a long time to develop from onset to abnormal thyroid function. It can present directly as hypothyroidism or it can first appear hyperfunctional but eventually develop into hypothyroidism. There is usually fatigue and weakness, fear of cold, depression, late menstruation, low volume and leucorrhea in women; impotence in men. There are symptoms such as little food and bloating, poor digestion, sticky and unpleasant stools, insubstantial sleep or difficulty in falling asleep, and easy waking. Atypical manifestations: for example, thyrotoxicosis. Hashimoto’s thyroiditis presents with thyrotoxicosis in two ways: Hashimoto’s hyperthyroidism and Hashimoto’s pseudohyperthyroidism (transient hyperthyroidism). Hashimoto hyperthyroidism refers to Hashimoto’s thyroiditis combined with hyperthyroidism, or Hashimoto’s combined with toxic diffuse goiter. The clinical features include hyperthyroidism with hyperthermia, excessive sweating, hand tremors, weight loss, etc. The thyroid gland is enlarged, tough, and may have vascular murmurs; there may be infiltrative proptosis and anterior tibial mucinous edema. Hashimoto’s pseudohyperthyroidism is caused by thyroid destruction and thyroid hormone release. Generally, the symptoms are mild and the disease is easy to control. The iodine uptake rate of the thyroid gland is reduced and the rapid decline of thyroid function is easy to occur rapidly after the application of anti-thyroid drugs. Therefore, most patients with Hashimoto’s thyroiditis have an insidious onset and are difficult to detect early. For those at high risk with a family history, regular checkups should be performed for early detection and treatment.