Ultrasound examination can detect liver cancer. Ultrasound examination combined with blood methemoglobin concentration test is the preferred examination method for early stage liver cancer patients. Through ultrasound examination, the specific shape, size and location of liver cancer masses can be observed, and whether there are cancer clots in the hepatic vein and portal vein can also be distinguished, and the accuracy rate is generally high, reaching over 90%. If the liver tumor is small or precancerous, which cannot be detected by ultrasound in time, CT, MRI or PET-CT is needed for clarification. If a patient has liver cancer, ultrasound examination will show significant changes in liver morphology, with occupying lesions in the liver, irregular margins and increased echogenicity in the liver. Patients who usually smoke, drink alcohol or have hepatitis B, hepatitis C or alcoholic cirrhosis should be alert to the occurrence of liver cancer. For patients with higher risk of liver cancer, they should go to the hospital regularly for liver ultrasound examination and should be diagnosed and treated promptly when abnormalities are detected.