The main etiological factors of liver cancer in China include hepatitis virus infection, food aflatoxin contamination, long-term alcohol abuse and blue-green algae toxin contamination of rural drinking water, other liver metabolic diseases, autoimmune diseases and cryptogenic liver disease or cryptogenic cirrhosis. Since early diagnosis of liver cancer is crucial for effective treatment and long-term survival, early screening and early surveillance of liver cancer are highly emphasized. Routine surveillance screening indicators mainly include serum alpha-fetoprotein (AFP) and liver ultrasonography (US). For men ≥40 years of age or women ≥50 years of age with HBV and/or HCV infection, alcoholism, comorbid diabetes mellitus, and a family history of liver cancer at high risk, screening is generally performed every 6 months. Pre-subclinical stage of hepatocellular carcinoma refers to the period from the beginning of the lesion to the diagnosis of subclinical hepatocellular carcinoma when the patient has no clinical symptoms and signs and is difficult to detect clinically, usually about 10 months. In the subclinical stage (early stage) of hepatocellular carcinoma, the tumor is about 3-5 cm, most patients still have no typical symptoms and the diagnosis is still difficult, mostly detected by serum AFP census for about 8 months on average, during which a few patients can have symptoms related to chronic underlying liver disease such as epigastric stuffiness, abdominal pain, weakness and loss of appetite. Therefore, those who have high-risk factors and develop the above conditions should be alerted to the possibility of liver cancer. Once typical symptoms appear, the disease has often reached the middle or advanced stage of liver cancer, at which time, the disease develops rapidly, with a total of about 3-6 months. It is often intermittent or persistent vague, dull or distending pain, which increases with the development of the disease. If the tumor invades the diaphragm, the pain may spread to the right shoulder or the right back; the tumor growing backward to the right may cause pain in the right lumbar region. The cause of pain is mainly due to the tumor growth which makes the liver envelope tense. The sudden occurrence of severe abdominal pain and peritoneal irritation sign may be caused by peritoneal irritation due to rupture and bleeding of subperitoneal cancer nodules. 2.Loss of appetite, epigastric fullness after meals, indigestion, nausea, vomiting and diarrhea, etc. are easily ignored because of the lack of specificity. 3, wasting, weakness, general weakness, a few patients in advanced stage may present a cachexia condition. 4.Fever is more common, mostly persistent and low fever, 37.5-38℃, but it may be irregular or intermittent, persistent or spontaneous high fever, similar to liver abscess, but no chills before fever, and antibiotic treatment is ineffective. The fever is mostly cancer fever, which is related to the absorption of tumor necrotic material; sometimes it can be caused by cholangitis due to the compression or invasion of bile ducts by the cancer, or fever due to other infections combined with the weakened resistance. 5.Symptoms of extrahepatic metastases such as lung metastases can cause cough and hemoptysis; pleural metastases can cause chest pain and bloody pleural effusion; bone metastases can cause bone pain or pathological fracture, etc.