With the maturation of transplantation surgery techniques and the application of new generation immunosuppressive agents and organ preservation fluids, liver transplantation has become the most effective method that can successfully save end-stage liver disease. Immune rejection has been a major concern for recipient survival, however, with the successful use of immune transplantation agents such as FK506 and MMF, it has become less and less of a threat to recipient survival; instead, infection has become one of the leading causes of recipient death. Transplant infections are classified in epidemiology as immunodeficiency infections or immunosuppression-related infections. In recent years, due to the misuse of broad-spectrum antibiotics and some reasons in the social and natural environment, the epidemiology of bacteria has changed significantly compared to a decade ago, with a significant increase in opportunistic and drug-resistant bacteria and the emergence of some rare bacterial infections and opportunistic infections, and liver transplant infections are more challenging in this general context. What are the characteristics of infection in liver transplantation and how to prevent and treat the infection, this paper will give the readers some clarified views and good experiences on this issue. I. Risk factors for infection after liver transplantation: Infection in liver transplantation depends on two factors, namely the state of immunosuppression of the recipient and the intensity of exposure to risk factors for infection. The donor factor is the most neglected, there are more living and donor organs abroad, the bacteraemia of the donor can easily cause bacterial translocation; domestic cadaveric liver transplantation dominates, although the quality of the donor is better, but the contamination of the taken liver can also cause bacterial translocation, our transplantation center found four bacterial translocation, they are: Staphylococcus haemolyticus, Staphylococcus xylosus, Acinetobacter Staphylococcus haemolyticus, Staphylococcus xylosus, Bacillus cereus, and Bacillus maltophilia. In addition, donor hepatitis B virus can cause the reoccurrence of hepatitis B in the recipient, and with 120 million hepatitis B virus carriers in China, standardized management of donor resources is imperative. Transplantation environment is important in many hospitals as hardware construction, such as transplantation ward, sterile ICU, transplantation operating room, transplantation access, transplantation examination equipment (bedside ultrasound, bed x-ray camera), but more emphasis should be placed on the aseptic management of transplantation ward. Recipient factors include preoperative, intraoperative and postoperative factors. Summarizing the high-risk factors for postoperative infection in City One liver transplantation, it was found that the preoperative risk factors are liver transplantation for fulminant liver failure, retransplantation, recent infection, hepatorenal syndrome, with CMV infection and hepatic encephalopathy, and severe ascites; the intraoperative risk factors are unsatisfactory hepatic artery portal vein anastomosis, biliary-intestinal anastomosis, liver-free period more than 90m, operation time >10h, and The postoperative risk factors are tracheal intubation time >5d, TPN treatment >1w, anti-rejection therapy, postoperative bleeding, re-abdominal surgery, and misaspiration, etc. Recognizing susceptibility factors, distinguishing high-risk recipients, and intervening in them early is the first step to consider for infection control. The characteristics of bacterial infections after liver transplantation: 1. First, the vast majority of liver transplant recipients have at least one bacterial infection, and 2/3 of them have more than one serious infection. 2, bacterial infections are mainly recent infections, occurring within 2 weeks, with the highest rate of pulmonary infections, followed by abdominal and biliary tract infections. 3.Bacterial flora change: G+ has a tendency to increase, G- bacteria in Escherichia coli, Pseudomonas aeruginosa decreased, immobile bacilli, Yinchou bacilli increased, G+ bacteria in lysis, gin, enterococci significantly increased, the emergence of some rare bacteria such as Acinetobacter baumannii, maltophilia. 4, the lung and abdominal cavity showed mixed infection, the lung in addition to common Staphylococcus aureus, lysozyme, there are also Acinetobacter baumannii, maltophilia and other rare G-bacteria infection; abdominal cavity in addition to Escherichia coli, gutter bacilli, there are enterococci, lysozyme and other G+ bacteria infection. 5, ESBL and MRSA drug sensitivity test in coccobacillus variability: G+ bacteria MRSA positive rate is high; G- bacteria in Klebsiella pneumoniae, Escherichia coli ESBL more negative, indicating that G- bacteria in the resistance is relatively weak. G- bacteria the most sensitive antibiotic is imipenem, G+ bacteria the most sensitive is vancomycin. Third, the principles of treatment of post-liver transplantation infection: 1. Screen high-risk patients according to infection-related factors and perform preventive interventions. 2. Daily culture and drug sensitivity tests of various drains, secretions and body fluids are performed in the monitoring ward, and a surveillance system of bacterial epidemiology is established. By establishing a database of bacterial fungal infections in liver transplantation centers, namely WHONET5.3 bacterial database, our center can regularly obtain (every 3 months) epidemiological reports on the etiology of infections in liver transplantation centers to guide the rational use of clinical antibiotics, from which The benefits are enormous. 3, according to fever, bacteriology, and clinical evidence into evidence infection, clinical infection, pathogenic infection, and unexplained infection. In addition, infection prevention and control should be adjusted in several aspects such as immunosuppression protocol, postoperative nutritional modalities and ward management to reduce the rate of postoperative infection. 1. Choose a combined suppression program to reduce the dose and duration of medication; choose a treatment program without hepatic and renal toxicity for patients with renal dysfunction, such as low-dose FK506 + rapamycin or low-dose hormone + rapamycin; reduce the dosage of primaquine or discontinue it for those with existing infection. 2, enteral nutrition is better than TPN: early progressive enteral nutrition reduces intestinal flora translocation, nutrients are metabolized by the liver and not directly into the body circulation, which is conducive to the recovery of liver function and promotes protein synthesis. 3.Strengthening isolation and protection in the ward is the basic condition to reduce nosocomial infection. 4, The cause of infection must be discharged, such as complications of vascular and biliary tract, abdominal and hepatosplenic abscesses should be treated actively, including ERCP, ETU, endoluminal vascular and surgical treatment. Finally, it is emphasized that there are no real medication guidelines, only the establishment of epidemiological surveillance systems for bacteria in the respective transplantation centers, so that the anti-infection treatment can go from empirical medication to the path of evidence-based medicine.