Secondary liver cancer, also known as liver metastatic cancer, is a type of lesion that occurs in the liver due to metastasis from malignant tumors in other parts of the body. It has a high incidence rate and poor prognosis, and is one of the main causes of death for patients with advanced tumors. This article systematically reviews the research progress in epidemiology, pathogenesis, clinical characteristics, and prognosis of secondary liver cancer caused by different primary tumor sources. The article first elaborates on the basic concepts and metastasis mechanisms of secondary liver cancer, and then focuses separately on the clinical characteristics and research status of liver metastasis caused by common primary tumors such as colorectal cancer, neuroendocrine tumors, gastric cancer, gastrointestinal stromal tumors, pancreatic cancer, biliary tract tumors, breast cancer, female reproductive system tumors, lung cancer, melanoma, and kidney cancer. Through the review of the incidence rates, metastasis patterns, molecular biological characteristics, and treatment strategies of each type of liver metastasis, this article reveals the significant heterogeneity of secondary liver cancer at the level of primary tumor types, and emphasizes the importance of individualized treatment strategies in clinical practice. Future research should further explore the molecular mechanisms of different types of liver metastasis, optimize conversion therapy and surgical timing, in order to improve patient prognosis.