Diabetes mellitus caused by pituitary tumor has the possibility of cure. Functional pituitary tumor can cause abnormal hormone secretion, which may lead to abnormal increase in the secretion of growth hormone, adrenocorticotropic hormone, thyroid stimulating hormone, etc., which may lead to increased secretion of glucagon, thyroid hormone and other glucose-raising hormones, resulting in abnormally high blood glucose levels, thus causing diabetes mellitus. Pituitary tumors that cause abnormal secretion of hormones and lead to diabetes can be treated with medication, surgery, and radiation therapy. Surgical treatment reduces the secretion of blood glucose-raising hormones by removing the pituitary tumor, and this type of diabetes can be cured. When pituitary tumor causes diabetes, it is recommended to consult a doctor in time and take appropriate treatment plan under the doctor’s guidance.