High ACTH value may be caused by primary hypoadrenocorticism, Cushing’s disease, ectopic ACTH syndrome, etc. Diagnosis should be made by combining other laboratory results and imaging tests such as nuclear magnetic resonance imaging, as the causes of the disease are different, and the hazards to the human body are also different. 1. Primary hypoadrenocorticism: ACTH is a hormone secreted by the pituitary gland, which can act on the adrenal cortex and promote the secretion of adrenocorticotropic hormone, and at the same time, it is subject to the negative feedback regulation of adrenocorticotropic hormone. When the adrenal cortex is not functioning properly, the level of secreted corticotropin decreases, resulting in excessive secretion of ACTH. 2. Cushing’s disease: ACTH microadenoma of the pituitary gland leads to excessive secretion of ACTH by the pituitary gland, and at the same time, excessive secretion of adrenocorticotropic hormone, which leads to the manifestations of Cushing’s syndrome, such as centripetal obesity, full-moon face, and purple lines on the folds of the skin. 3. Ectopic ACTH syndrome: it can be caused by tumors in other parts of the body, such as lung cancer. If high ACTH value is found in the examination, the relevant examination should be perfected according to the doctor’s instruction, the cause should be clarified and the treatment should be standardized.