The most common malignant tumor of the liver is primary hepatocellular carcinoma. Besides primary hepatocellular carcinoma, there are other malignant tumors of the liver such as secondary hepatocellular carcinoma, hepatic sarcoma, hepatoblastoma and cystadenocarcinoma. Secondary liver cancer is the most common malignant tumor other than primary liver cancer. Malignant tumors of the gastrointestinal tract, pancreas, lungs, breast, bones, prostate, and other organs can metastasize to the liver. Diagnosis relies on ultrasound and CT to visualize multiple tumors in the liver, and patients tend to have a history of surgery for malignant tumors in other organs or malignant tumors examined in those organs. Hepatic sarcoma is a rare malignant tumor of the liver, which is a malignant tumor originating from vascular endothelium, smooth muscle and other tissues. Diagnosis relies on ultrasound and CT showing hyperechoic, or hypodense, occupations with negative alpha-fetoprotein. Treatment is based on surgical resection. Hepatoblastoma is a common malignancy in childhood, with approximately 90% occurring under 5 years of age, and more than 90% are alpha-fetoprotein positive, with elevated levels higher than those of primary hepatocellular carcinoma. The diagnosis can be made based on history and CT and other examinations. Treatment is mainly surgical, and chemotherapy can be used for those who cannot be operated. Cystadenocarcinoma is malignant from cystadenoma of intrahepatic bile duct epithelium, with negative alpha-fetoprotein. Diagnosis mainly depends on the cystic intrahepatic space seen on ultrasound and CT, and the difference between cystadenocarcinoma and hepatic cyst or cystadenoma is that cystadenocarcinoma has thicker cystic wall, with uneven inner wall, papillary protrusion, and there is often a separation inside the cyst. Surgical resection is the main treatment.