Lung cancer fever does not have a fixed time every day. It should be clear that there are many different conditions causing lung cancer fever, such as common infections, because lung cancer is a tumor of the respiratory system, often accompanied by bacterial-viral or even mycological infections, which are not very typical and have a fixed time of fever. In addition, post-treatment fever is due to a kind of post-inflammatory injury caused by, for example, chemotherapy or radiotherapy. Brain metastasis can occur in lung cancer, and brain metastasis can cause fever if it compresses the thermoregulatory center of the inferior optic thalamus, and central fever can also occur, although it is not common. Typical tumor fever is fever due to extensive necrosis of the tumor. Among the above fever types, tumorigenic fever is sometimes fixed in time, that is, it occurs every day, often in the middle of the afternoon and evening, and slowly subsides after treatment, but not always. In a wide group of patients, the fever will not have a fixed time, and the most critical thing is to clarify the cause of the fever and treat it symptomatically.