Glutamyl transpeptidase (GGT) is an enzyme that catalyzes the γ-monoglutamyl group transfer reaction and is widely present in various tissues such as liver, gallbladder, pancreas, heart, kidney and prostate, and is particularly abundant in liver, kidney and pancreas, but the serum glutamyl transpeptidase is mainly derived from the hepatobiliary system. GGT is widely distributed in the liver on the capillary side of the hepatocytes and throughout the biliary system. Clinically, the normal value of glutamyl transpeptidase is 3-50 U/L. An increase to about 300 U/L indicates hepatocellular damage, which has an impact on the patient’s liver function. The causes of elevated glutamyl transpeptidase include both medical and surgical causes. Internal causes include fatty liver, alcoholic liver, various types of viral hepatitis, liver cirrhosis, autoimmune liver disease, and drug-related liver injury. In addition, poor rest, overeating, exertion, and strenuous activity can cause a mild increase in glutamyl transpeptidase. Surgical causes include various types of intra- and extra-hepatic bile duct stones, benign and malignant liver tumors, hepatic occupying lesions, cholestatic liver disease, etc. Generally, the lesion cannot be clarified by elevated glutamyl transpeptidase alone, but should be further clarified by combining with other imaging and laboratory tests, and targeted treatment is needed for different causes.