Persistent high fever that does not go away is commonly seen in diseases such as fever caused by viral infection, lung abscess, and lung tumor occupancy. Further examination can be done to clarify the diagnosis. Routine examination includes blood routine, blood sedimentation, C-reactive protein and chest X-ray, and chest CT, tumor markers and fiberoptic bronchoscopy can be examined if necessary. If the fever is caused by viral infection, it can be treated symptomatically with antiviral drugs, such as ribavirin. It can be combined with Chinese patent medicines such as Blue Scutellaria Oral Liquid and Shuanghuanglian Oral Liquid to clear the fever and detoxify the virus and antiviral medicines. If the fever is caused by epidemic virus, you can take oseltamivir phosphate capsule orally, 75mg each time for adults, twice a day, 5 days for a course of treatment, which can prevent and control the influenza virus attack. If the fever is caused by lung abscess, antibiotic drugs can be used to control the infection in the lungs, and the treatment period is longer. If it is high fever caused by lung tumor occupying, and it does not go down, surgery is recommended, and radiotherapy and chemotherapy are recommended for those who have no indication for surgery.