ALP is an alkaline phosphatase enzyme that is mainly found in the liver, bones, kidneys and other organs. The normal value in adults is 40-100 U/L, and in children it is usually less than 250 U/L. ALP has six other isoenzymes with the same nature, namely ALP1-ALP6. The presence of increased alkaline phosphatase usually points to the following conditions: 1. Biliary obstruction, suggesting the presence of biliary obstruction diseases inside and outside the liver, such as biliary stones, primary biliary cirrhosis, intrahepatic cholestasis, etc. In addition, the possibility of pancreatic head cancer is not excluded. Also do not exclude the possibility of pancreatic head cancer at this time ALP is significantly elevated, usually accompanied by the presence of ALP1 and ALP1>ALP2. 2, liver disease, acute hepatitis, cirrhosis patients often have increased ALP. 3, ALP increase in the situation helps to identify different types of jaundice, if the jaundice is caused by extrahepatic biliary tract obstruction, ALP is significantly increased. In case of hepatocellular jaundice ALP is mildly increased and in case of intrahepatic biliary obstruction ALP is significantly increased.4. Skeletal diseases, fracture healing period, fibrous osteitis, osteosarcoma, rickets, bone metastases, etc. can be considered.