Liver transplantation for hepatocellular carcinoma is the most complete for the radical treatment of the tumor. It is because liver transplantation can completely eliminate the liver tumor and possible metastatic lesions in the liver, and also eliminate the original liver sclerosis stroma (most hepatocellular carcinoma patients are accompanied by cirrhosis), therefore, many hepatocellular carcinoma patients choose liver transplantation treatment, thus gaining a new life and a chance for long-term survival. However, even though the original liver (including all intrahepatic tumors) has been removed, the possibility of metastasis to other sites (most commonly the lung) and transplantation liver metastasis still exists after surgery, because, as long as liver cancer is early or intermediate or late, there is the possibility of extrahepatic metastasis before surgery, and the absence of metastasis outside the liver in all preoperative examinations does not completely mean 100% absence of metastasis (because the current scientific and technological Therefore, in order to make sure that each patient can receive appropriate treatment, experts at home and abroad have been devoted to studying what kind of liver cancer patients are suitable for liver transplantation. So far, there are many standards at home and abroad, among which the most representative ones are Milan standard and University of California standard, as follows: 1. Milan standard: liver cancer with single tumor diameter ≤ 5.0cm, multiple tumors totaling no more than 3, maximum tumor diameter < 3.0cm, total diameter no more than 8.0cm, no vascular invasion This type of liver cancer can be treated with liver transplantation. Such hepatocellular carcinoma can be treated by liver transplantation with similar effect as benign disease. 2. University of California criteria: single tumor diameter ≤ 6.5cm, multiple tumors not more than 3, maximum tumor diameter ≤ 4.5cm, total diameter ≤ 8.0cm, whose survival rate is not significantly different compared with Milan criteria. Patients selected according to the above criteria can get better results, however, patients who exceed the above criteria are not said to be unable to perform liver transplantation, but the chance of metastasis after liver transplantation is relatively higher.