Pituitary tumors may affect the secretion of thyroid hormones. If a pituitary tumor causes an overproduction of thyrotropic hormone, it may promote thyroid hormone secretion by the thyroid gland, leading to hyperthyroidism. Patients with pituitary tumors, which are tumors originating from the adenopituitary gland, the neuropituitary gland, and the residual squamous epithelial cells of the embryonic craniopharyngiocysts, may suffer from either excessive hormone secretion or insufficient hormone secretion. Clinically, they can be classified into prolactinoma, growth hormone tumor, adrenocorticotropic hormone tumor, thyrotropic hormone tumor and so on according to their function of hormone secretion. In case of thyrotropinoma, it may lead to symptoms of hyperthyroidism such as panic, weight loss, frequent bowel movements, excessive sweating and insomnia. Therefore, pituitary tumor may affect the secretion of thyroid hormone. Pituitary tumor patients are advised to clarify the type of disease in time and take reasonable treatment according to the doctor’s prescription to avoid affecting their health.