Alpha fetoprotein (AFP) is a glycoprotein that contains about 3% sugar and has a molecular weight of approximately 70000 fetoprotein. The diagnosis of hepatocellular carcinoma (HCC) with alpha fetoprotein (AFP) requires not only observation of its absolute value, but also observation of its dynamic changes. The rise and fall of its concentration is of great value for the development of the disease, observation of therapeutic effects, and observation of liver cancer recurrence. Under normal circumstances, this protein mainly comes from embryonic liver cells. About two weeks after birth, alpha fetoprotein disappears from the blood, so the content of alpha fetoprotein in normal human serum is very low, less than 20 micrograms/liter; However, when liver cells undergo cancerous transformation, the function of producing this protein is restored, and its content in the serum increases sharply as the condition worsens, making alpha fetoprotein a specific clinical indicator for diagnosing primary liver cancer.