The causes of low fever after lung cancer surgery can be categorized into three kinds, i.e. postoperative absorption fever, infectious fever and cancerous fever. 1. Postoperative absorption fever, mainly low fever, which is the fever caused by the body absorbing some residual tissue fluids in the body, will usually subside within 3 days. Generally, the fever will subside within 3 days. Generally, the patient should be closely observed or the temperature should be lowered physically. 2. Infectious fever, if lung cancer patients have wound infection, lung infection or urinary tract infection, it can also cause fever, and high fever is common, while some patients have low fever. Doctors will usually adopt certain anti-inflammatory and anti-infection drugs for treatment, and cooperate with physical cooling. 3. Cancer fever refers to the non-infectious fever directly related to cancer and the fever caused by treatment during tumor development when infection is excluded and antibiotic treatment is ineffective. The patient’s temperature is usually between 37.5-38 degrees Celsius. Application of antibiotics and anti-allergic drugs has no obvious effect, but the fever can be reduced after application of anti-cancer drugs. If lung cancer patients develop low fever after surgery, they should report to their attending physician immediately to clarify the cause of the disease and receive standardized treatment.