Ultrasonography can categorize fatty liver into mild, moderate and severe according to the changes of near-field echoes and far-field echoes. 1. Mild fatty liver: ultrasonography shows that near-field echoes are fine and enhanced, far-field echoes are weakened and inconspicuous, intrahepatic blood vessel wall and diaphragm can be shown, hepatic veins are thinned, and there is no obvious change in the size of the liver. 2. Moderate fatty liver: ultrasonography can find that the near-field echoes are more dense and moderately enhanced, the far-field echoes are weakened, the intrahepatic ductal structures can be shown more ambiguously, and the liver is mildly enlarged. 3. Severe fatty liver: ultrasonography can show that near-field echoes are obviously thickened and increased, far-field echoes are obviously weakened, and intrahepatic bile ducts are ambiguous. Patients with fatty liver are recommended to seek medical treatment in time and intervene under the guidance of specialized physicians to avoid delaying the condition.