Abstract: In recent years, the incidence of liver metastasis from colorectal cancer has continued to rise, posing a significant threat to human health and life.Although traditional treatments such as surgery and chemotherapy have shown some efficacy in certain patients, options remain limited for those who are not surgical candidates or are resistant to chemotherapy.Yttrium-90 microsphere selective internal radiation therapy, as an innovative local treatment, has fully demonstrated its effectiveness and safety in treating colorectal cancer liver metastasis patients. The authors review the research background, mechanisms, and principles of yttrium-90 microsphere selective internal radiation therapy in the field of colorectal cancer liver metastasis, and to explore its application progress in clinical practice, aiming to provide clinical doctors with more comprehensive and detailed reference information, with the goal of improving treatment outcomes and quality of life for colorectal cancer liver metastasis patients.