Colorectal cancer is the third high incidence of tumor in the world,and liver is one of the most common sites of distant metastasis.Liver metastasis accounts for 50％-75％ in distant metastasis.Only about 10％ -15％ of patients are candidates for resection,and the recurrence is easy.Selective internal radiation therapy is a new type of radiotherapy.It is partial and liver-targeted.For unresectable colorectal liver metastasis,selective internal radiation therapy alone or in combination with other therapies can reduce cancer focus,prolong the survival,and maybe improve overall survival.