Fatty liver is a lesion caused by excessive accumulation of fat in liver cells due to various reasons. Fatty liver disease is a serious threat to the health of the nation, becoming the second most common liver disease after viral hepatitis, a common cause of cirrhosis, and can develop into liver cancer, increasing the medical burden on families and society. The total amount of fat in the liver of a normal person accounts for about 5% of the liver weight, and the amount of fat over 5% is mild fatty liver, over 10% is moderate fatty liver, and over 25% is severe fatty liver. When the total fat in the liver exceeds 30%, it can be detected by ultrasound and diagnosed as “fatty liver” by ultrasound. In patients with fatty liver, the total fat can reach 40%-50%, and some reach more than 60%. Because of the liver’s strong compensatory capacity, only when it has developed to a very serious degree will symptoms appear and attract attention. Fatty liver includes alcoholic liver disease and non-alcoholic fatty liver disease. Its pathological types include simple fatty liver, steatohepatitis and cirrhosis, and it can develop into liver cancer. Therefore, fatty liver is also a disease. The key to prevention and treatment is early detection and early treatment, and people’s health education is especially important.