Fatty liver sonography refers to the fatty liver manifestations appearing on imaging. Fatty liver suggests hypodense changes on ultrasound, and if it is diffuse fatty liver, it shows hypodense changes throughout the liver, and the liver can be enlarged, especially the enlarged liver caused by alcoholic fatty liver is more obvious. If it is hypodense change on CT image, the density ratio of liver to spleen density ≤ 1 is the criterion for diagnosing fatty liver, and the severity of fatty liver can be judged according to the ratio of liver and spleen density. If the fatty liver is focal on ultrasound, it can be shown as heterogeneous density of the liver, some with low density and some with slightly higher density. Ultrasound and CT examinations are more commonly used clinical tools to diagnose fatty liver with high specificity. The positive rate of diagnosis can reach more than 70%-80%, and it is non-invasive and has less impact on the human body.