There are many reasons for boys’ body fever, such as physiological factors, infectious factors, non-infectious factors and so on. 1. Physiological factors: boys will have fever after mental stress and strenuous exercise. This phenomenon is physiological, usually without special treatment. 2. Infectious factors: boys due to a variety of pathogenic infections, such as bacteria, viruses, rickettsiae, etc., can also cause fever. 3. Non-infectious factors: boys with lymphoma, leukemia, hyperthyroidism, systemic lupus erythematosus encephalitis and other diseases, will also appear the phenomenon of body fever. There are many reasons that cause fever in boys, if we exclude physiological factors, we suggest that we go to the hospital in time to improve the examination, clear diagnosis, and give standardized treatment after identifying the cause.