Ultrasound is one of the main examination methods for liver cancer, which has the advantages of being less painful, non-invasive and inexpensive. Ultrasound for liver cancer is described from the following aspects: i. Envelope, liver cancer is often accompanied by fibrous pseudo-envelope, whose acoustic impedance is higher than that of the surrounding liver tissue and the cancer, thus forming an interface reflection. The intra-tumor echogenicity varies in height and has a tendency to be variable, and can be hypoechoic, hyperechoic, mixed echogenicity and isoechoic; third, color blood flow in cancer nodes. Pulsatile arterial blood flow spectrum can be measured, and continuous portal venous blood flow can also be seen in the periphery; fourth, cancer embolism, ultrasound examination can detect cancer embolism in portal vein system, hepatic vein system or biliary tract system. The above aspects are what ultrasound of liver cancer should describe.