It is common for cancer patients to have fever due to tumor depletion or low food intake, resulting in low immunity or further decrease of immunity due to radiotherapy, combined with infection, and many patients eventually die from infection. How to prevent infection when you have tumor? Patients or their family members will definitely benefit from knowing this knowledge. First, there should be the awareness of infection prevention. This kind of awareness runs through all aspects of the life of tumor patients, so that they can do a good job in details, prevent cold and keep warm, avoid direct blowing of air conditioners in hot days, avoid activities everywhere during flu season, avoid overworking, avoid staying up late, ensure sleep and regulate emotions, etc. Especially after surgery and during radiotherapy, they should be extra careful. Second, strengthen the body nutritional support. Encourage patients to eat more high-protein, high-nutrition, vitamin-rich foods. For those who have poor gastrointestinal function or insufficient food, strengthen parenteral nutrition as much as possible, and oppose “starvation therapy for tumor”. Thirdly, enhance the immunity of the body. Encourage patients to exercise moderately, feasible eight-danjin, taijiquan, etc. to strengthen the body and move the muscles and bones; or moderate use of immune enhancers, such as thymopentin, interleukin 2, etc.; fourth, the reasonable use of whitening needles. Tumor patients are most likely to have serious infections during the period of bone marrow suppression after radiotherapy and chemotherapy, so timely review of blood routine and timely and correct administration of granulocyte colony-stimulating factor (leukostimulation injection) can rapidly enhance white blood cells and prevent the occurrence of infection. Fifthly, the rational application of Chinese medicine. The most recognized and reliable Chinese medicine for tumor treatment is to support the body’s positive energy and enhance the immunity of the body. After surgery and radiotherapy, the combination of Chinese herbal medicine treatment can achieve twice the effect with half the effort.