Liver cysts are a relatively common benign disease of the liver, and the majority of liver cysts are congenital, that is, they are formed due to some congenital developmental abnormality. Most of the causes of liver cysts are due to developmental disorders of small intrahepatic bile ducts, and solitary liver cysts occur due to ectopic bile ducts. Acquired factors are rare, for example, in pastoral areas, if people are infected with encapsulated cysticercosis, parasitic cysts are produced in the liver. Trauma, inflammation, and even tumors can also cause liver cysts. Cysts can be single or as many as dozens, and the size of cysts can range from 0.5 cm to 30 cm. Patients with polycystic liver cysts are sometimes combined with cysts of other internal organs, such as concomitant renal cysts, pulmonary cysts and occasionally pancreatic cysts and splenic cysts. In polycystic liver, the cysts can be all over the liver. We once met a patient with polycystic liver, whose diseased liver weighed 26 pounds and seriously affected his working life, and later recovered by liver transplantation. Liver cysts grow slowly, so they may be asymptomatic for a long time or for life. Their clinical manifestations also vary with the location, size and number of cysts, as well as with the presence or absence of pressure on adjacent organs and the presence or absence of complications. Liver cysts are usually asymptomatic. When the cyst grows to a certain extent, it may compress the gastrointestinal tract and cause symptoms such as epigastric discomfort and fullness; common complications of liver cysts are rupture and bleeding, bacterial infection, fistula and penetration, while cancer is rare. With the development and popularity of diagnostic imaging, especially ultrasound has been listed as one of the routine physical examinations of the population, and the detection rate of ultrasound for liver cysts can reach 98%, so many of them are found. However, in order to fully understand the size, number and location of cysts as well as the liver and related organs around the liver, especially for patients with huge liver cysts requiring surgical treatment, magnetic resonance examination is the most definite diagnosis and also has a guiding meaning for whether to operate or not. Sometimes some blood tests are still necessary for differential diagnosis, especially the AFP test to exclude primary liver cancer. Liver cysts will neither affect liver function nor develop into liver cancer, so a relatively small cyst (less than 4 cm) is usually not necessary and should be reviewed regularly. However, if the diameter is larger than 5-8cm, symptoms such as indigestion, nausea, vomiting and right upper abdominal discomfort or pain may occur.