Malignant tumors from various parts of the human body metastasize to the liver by four routes: portal vein, hepatic artery, lymphatic pathway and direct infiltration, so metastatic cancer of the liver is very common in clinical practice. In recent years, there has been a great progress in the treatment of liver metastatic cancer. Due to the improvement of the follow-up system, the application of new imaging techniques and the detection of serum markers, patients with secondary liver cancer have more chances to obtain early diagnosis and early treatment, and their survival rate has been improved accordingly. The treatment of secondary liver cancer needs to be combined with the treatment of primary foci at the same time. The current treatment methods include surgical resection, chemotherapy, hepatic artery embolization chemotherapy and biological therapy. 1.Hepatectomy: Except for carcinoid tumor, all visible liver metastases should be removed as much as possible in the absence of extrahepatic metastases. It is generally considered that liver metastasis of colorectal cancer is the best indication. In addition, secondary hepatocellular carcinoma of Wilm tumor, smooth muscle sarcoma and uveal melanoma also have better efficacy after hepatic resection. If there is no contraindication, local secondary hepatic tumor resection should be considered as the treatment of choice with the incision margin at least 50 px from the tumor. if the secondary hepatocellular carcinoma is large, hepatic resection can be performed 4-6 weeks after colorectal cancer resection. Surgical complications of secondary hepatocellular carcinoma are mainly infection and liver failure, and the death rate is about 4%-20%. The causes are related to the extent of hepatectomy, intraoperative bleeding and damage to tissues, etc. For patients with cirrhosis, hepatectomy is generally not performed. 2, hepatic artery infusion chemotherapy (TAI) or chemoembolization (TACE): Bterman et al. (1950) first created this method of treatment, the 1960s party compelling, until the 1970s due to the perfection of operational techniques and complications significantly reduced and widely used. However, the choice of drugs used, the indications and the dosing regimen are still inconclusive. Currently, it is believed that HAI and TACE can be used for patients with unresectable liver metastases without extrahepatic lesions or with small extrahepatic lesions. Contraindications include extensive liver tumor lesions with jaundice, ascites or poor general condition. Since most of the liver metastases are asymptomatic or mildly symptomatic, prolonged survival should be considered as the main indicator of success of HAI or TACE treatment. The rationale of this therapy is based on the anatomical observation that most liver metastases are supplied by the hepatic artery, and therefore HAI can selectively kill tumor cells. The advantages of HAI are less systemic adverse effects, but hepatotoxic reactions. In addition to jaundice and liver function impairment, delayed biliary cirrhosis has been reported. The catheter can be inserted through the abdomen to observe the whole picture of the liver metastases, and the placement of the catheter is indeed fixed firmly; while the catheter is easy to slip and the drug infusion is not sufficiently satisfactory, which may cause gastrointestinal irritation, and also prone to infection and sepsis. It is believed that HAI or TACE is only locally effective for liver lesions, and lung, abdominal and bone metastases can still appear after applying this therapy. In addition, the size of the liver tumor, the presence or absence of metastases in the hilar lymph nodes, and the interval between the first surgery and the appearance of liver metastases are still the main factors determining the prognosis. Continued HAI or TACE is better than interval dosing for prolonging survival, so these factors need to be taken into account in future studies. It is also reasonable that symptomatic patients who have failed to respond to other therapies should be selected for study. It should be noted that if the disease deteriorates or the liver tumor continues to increase during chemotherapy, this treatment should be stopped in time. 3.Ablation therapy: Radiofrequency ablation (RFA) and microwave ablation (MWA) are physical ablation, which is a new technology of minimally invasive tumor treatment carried out in recent years, with wide indications, minimally invasive, safe, sure efficacy and light side effects. For lesions less than 87.5 px in diameter, it can achieve complete ablation and play a radical effect. For larger lesions, it can play a role in reducing the tumor load and can be used for patients who cannot be operated for various reasons. In addition, percutaneous transhepatic injection of anhydrous ethanol (PEI) or acetic acid (PAI) is chemical ablation, and of course, it can also achieve the efficacy achieved by physical ablation. 4. Chemotherapy by other routes: In the 1950s, fluorouracil (5-FU) was used for systemic chemotherapy via peripheral vein to treat colorectal cancer liver metastases, and the average remission rate was 15%-20%, but it could not prolong the survival. For breast cancer liver metastasis, systemic chemotherapy is still advocated, with doxorubicin (Adriamycimycin) being the most effective, and the remission rate can reach 25%-30%, which can be further increased to 50% if combined with other drugs. The combination of fluorouracil (5-FU), doxorubicin (Adriamycin) and mitomycin (mitomycin C) (FAM regimen) is still used for liver metastases from gastric cancer, with a remission rate of 25%-30%. Chemotherapy has a high remission rate for non-small cell lung cancer liver metastases, while it is slightly lower for those from melanoma. 5. Combined application of chemotherapy: In the early 1980s, some people applied degraded starch microspheres to temporarily block the capillary channels of small hepatic arteries, and then injected BCUN through hepatic arteries to increase the local drug concentration of liver tumors and reduce drug escape to the body circulation. In recent years, the Second Military Medical University Eastern Hepatobiliary Surgery Hospital has achieved certain efficacy in the treatment of liver metastatic cancer by applying hepatic artery chemoembolization combined with local injection of anhydrous ethanol. 6.Adjuvant therapy: This method is applicable to those who are likely to recur after radical surgery of primary cancer, those who are known that anti-cancer drugs are really effective or have less chance to be cured in case of recurrence, and those who have no adverse reactions to all adjuvant therapies. Most patients do not require the use of adjuvant chemotherapy after surgery. Methods to increase the concentration of relevant drugs in the tumor tissue to improve the therapeutic index include guided therapy with antibodies or liposomes, specific blockade of the toxic response to drugs with attenuating compounds or stimulation of bone marrow proliferation, and full use of fully implantable drug delivery systems (DDS). Improved regional all-implantable drug delivery systems can increase the concentration of drug per dose with the help of slowing down the flow rate of blood supply to the tumor. Currently, surgical resection and ablative therapy are the only methods to cure metastatic liver cancer for some lesions in the liver. If the lesion cannot be resected, palliative treatment is limited to improving quality of life and prolonging survival. There is still hope that designing the best combination of various therapies will change the final treatment outcome, and the discovery of more new drugs and new therapies is still expected in the future. In conclusion, if metastases are present in the liver, a treatment plan should be developed jointly by surgical, medical, oncologic, interventional, and radiotherapeutic physicians, with a comprehensive assessment of the disease to provide optimal treatment and close monitoring of the prognosis, and a multicenter collaborative prospective controlled study is important.