Liver hypodense shadow is the result of imaging tests such as ultrasound and CT of the liver. Liver hypodense shadow can be seen in many conditions, such as liver cysts, hepatic hemangiomas, hepatic encapsulation, liver cancer, and so on. 1. Liver cyst: It is a benign lesion. It is a cystic lesion containing internal plasma that does not communicate with the intrahepatic biliary tree. it appears as a round, well-demarcated, homogeneous density lesion on CT examination. For asymptomatic liver cysts, no treatment is usually necessary. For symptomatic patients, it can be treated by surgery and other methods. 2. Hepatic hemangioma: It is a common benign tumor of liver, among which cavernous hemangioma is the most common. Under CT, it is typically characterized by round or ovoid low-density lesions with clear boundaries. The disease can be treated by surgery, also by hepatic artery embolization and radiofrequency treatment. 3. Hepatic cysticercosis: it is a kind of zoonotic parasitic disease. under CT, it is a round low-density lesion. Ultrasonography shows thick-walled cystic lesions with cysts, active spots, etc. Surgery is the main treatment method. Surgery is the most important treatment. 4. Hepatocellular carcinoma: it is a common malignant tumor of liver, which is manifested as a low density lesion or nodule under CT. After enhancement, it has the manifestation of “fast in, fast out”, i.e. obvious enhancement in arterial phase, and decreasing enhancement in venous phase and delayed phase. Treatment modalities include surgical resection of the tumor, chemotherapy, interventional therapy, radiofrequency ablation, and so on. For patients with low-density shadow in the liver, they should go to the relevant departments of regular hospitals as soon as possible, and physicians will make a diagnosis according to the checklist and the patient’s condition and carry out appropriate treatment. Patients should not diagnose by themselves according to the checklist.