There are many reasons for elevated glutamyl transpeptidase, mainly in the following aspects: a. In acute viral hepatitis, hyper-synthesis of hepatocyte acylase adjacent to the necrotic area is one of the reasons for elevated glutamyl transpeptidase. Second, in chronic active hepatitis, glutamyl transpeptidase is often 1 to 2 times higher than normal, and if it is elevated for a long time, it may have the tendency of liver necrosis. In primary or metastatic hepatocellular carcinoma patients, most of glutamyl transpeptidase is moderately or highly elevated, which can be several times or even dozens of times higher than normal, while other system tumors are mostly normal. However, the single measurement of high glutamyl transpeptidase has no diagnostic value for hepatocellular carcinoma, but if methemoglobin and alkaline phosphatase are measured at the same time, the diagnostic value is greater. When intrahepatic or extrahepatic bile ducts are obstructed, the excretion of glutamyl transpeptidase is blocked and it flows back to blood with bile, which is one of the reasons for the increase of glutamyl transpeptidase. V. The change of serum glutamyl transpeptidase in cirrhosis depends on the activity of intrahepatic lesion and its etiology. Sixth, glutamyl transpeptidase is also often elevated in fatty liver patients, but most of the serum glutamyl transpeptidase activity does not exceed two times the normal value in general nutritional fatty liver. Seven, glutamyl transpeptidase is almost always elevated in patients with alcoholic hepatitis and alcoholic cirrhosis, which becomes an important feature of alcoholic liver disease. When there is elevated glutamyl transpeptidase in liver function test, we must find out the reason of elevated glutamyl transpeptidase, then combine with other indexes of liver function test to judge the condition comprehensively, in order to give targeted treatment.