Alkaline phosphatase in children is an important indicator of bone metabolism in children, which indirectly reflects parathyroid function, liver and biliary diseases, calcium and phosphorus metabolism of the organism, and bone growth. The normal range is less than 500 U/L for children younger than 12 years old and 40-150 U/L for children between 12 and 15 years old, but the normal values vary from hospital to hospital because of different test reagents and test methods. Children with increased alkaline phosphatase are considered to have the following causes: 1. Increased in physiological situations, because increased alkaline phosphatase is associated with bone growth and postprandial secretion of fat, etc. Therefore, an increase in alkaline phosphatase in children during the growth period is normal and does not require special treatment. However, the prerequisite is to exclude diseases of the hepatobiliary system and skeletal system.2. Diseases of the hepatobiliary system, various intra- and extra-hepatic biliary obstructive diseases can cause increased alkaline phosphatase.3. Skeletal diseases, such as rickets, osteochondrosis, osteoblastoma, etc., can also cause elevated alkaline phosphatase. When children have alkaline phosphatase 300 U/L, further examination of the hepatobiliary system, bone density and trace element testing are required, and symptomatic treatment is sufficient.