The difference between color ultrasound and B-ultrasound is that, in addition to displaying real-time images of organs like B-ultrasound, it can also display the internal blood flow status of organs. When using ultrasound to examine occupying liver lesions, ordinary B-ultrasound can only show the size and echogenic characteristics of liver cancer, and sometimes it is difficult to identify whether the occupying liver lesions are benign or malignant with ordinary B-ultrasound, but it is possible to identify them with color ultrasound. This is because the blood supply of hepatocellular carcinoma is different from that of benign hepatic occupations, and more than 90% of the blood supply of hepatocellular carcinoma is supplied by hepatic artery. Since color ultrasound can show the arterial blood flow inside liver cancer, it can distinguish liver cancer from benign occupancy based on the amount of arterial blood supply. If there is abundant arterial blood flow inside the occupying lesion, it indicates liver cancer, otherwise it indicates benign occupancy. The sensitivity of color ultrasound examination for liver cancer is similar to that of general ultrasound, but the examination cost of ultrasound is significantly lower than that of color ultrasound, therefore, general ultrasound examination should be performed first, and color ultrasound examination should be performed only when the nature of the occupying lesion is difficult to be determined by general ultrasound.