Childhood alkaline phosphatase is widely distributed in human tissues such as liver, bone, intestine, kidney and placenta. It is an enzyme excreted via the liver to the outside of the bile, but is not a single enzyme, but a group of isoenzymes. Clinical determination of alkaline phosphatase is mainly used for the diagnosis of diseases of the skeletal and hepatobiliary systems, especially for the differential diagnosis of jaundice. Alkaline phosphatase in children is an important indicator of the child’s bone metabolism, which indirectly reflects parathyroid function, hepatobiliary diseases, the body’s calcium and phosphorus metabolism and bone growth. Its normal value range is less than 12 years old, the normal value is less than 500 U/L; at the age of 12-15 years old, the normal value is 40-150 U/L. Children with increased alkaline phosphatase are considered to have the following causes: 1. Increased in physiological conditions, because increased alkaline phosphatase is associated with bone growth and fat postprandial secretion, etc. Therefore, an increase in alkaline phosphatase in children during the growth period is normal and does not require special treatment. The prerequisite is to exclude diseases of the hepatobiliary system and skeletal system; 2. Diseases of the hepatobiliary system, various biliary obstructive diseases within and outside the liver can cause increased alkaline phosphatase; 3. Skeletal diseases, such as rickets, osteochondrosis, osteoblastoma, etc., can also cause elevated alkaline phosphatase.