Colorectal cancer is common in China, with a high incidence of liver metastasis, and more than one-fifth of colorectal cancer is combined with liver metastasis at the time of diagnosis. Liver metastasis of colorectal cancer is one of the late manifestations of tumor, and the natural 5-year survival rate is low, but the 5-year survival rate can be up to nearly 50% after comprehensive treatment such as surgical resection. 1. Simultaneous resection of liver metastases and primary foci. The advantage is to avoid secondary surgery and reduce the pressure of patients. The disadvantage is that the surgery is more traumatic and new lesions may appear after surgery. 2.Staged resection Metastases are resected 2-3 months after resection of the primary foci. The advantage is that the surgery is less traumatic. Disadvantages secondary surgery has a psychological impact on the patient, and the tumor load is larger during tumor chemotherapy. 3.Surgical scope The surgery is aimed at achieving R0 resection and reducing surgical trauma. At least ensure that the functional residual liver volume accounts for at least 30% of the standard liver volume after surgery. 4.Surgical method For fewer lesions, anatomical hepatectomy is feasible. For multiple lesions, local resection of the tumor is feasible in order to preserve enough liver. 5.Residual liver modification If the residual liver is insufficient, the residual liver volume can be increased by portal vein embolization technique and operated after two weeks. Although the two-step hepatectomy technique combining liver dissection and portal vein ligation can also enlarge the residual liver, the surgery is traumatic, with many and serious complications, and there are certain objections. 6.Ablation therapy of metastases Ablation therapy can achieve better treatment effect for smaller lesions (75px), and the advantage is more significant for those who have difficulty in deep surgery alone. 7.Stage II treatment of unresectable lesions can be done through chemotherapy and radiotherapy to reduce the lesions, and then some patients can get the chance of surgery after re-evaluation. 8.Liver metastasis after colorectal cancer surgery The treatment of liver metastasis after colorectal cancer surgery focuses on liver lesions. According to the size, number, location and presence of extrahepatic metastases of liver metastases, the program is basically similar to that of simultaneous liver metastases.