The most common cause of painful urination with fever in children is urinary tract infection, such as urethritis and cystitis. It is necessary to do urine routine examination in time for clarification. 1. Urethritis: After the urethra is infected by pathogenic microorganisms, it will lead to congestion and edema of the urethral mucosa and ulceration, causing painful urination. Disease-causing microorganisms can cause fever if they enter the blood system. It needs timely anti-infection treatment, such as cephalosporin antibiotics. 2. Cystitis: If the urethritis is not treated in time, the pathogenic microorganisms will spread to the bladder along the urethra, thus causing cystitis, the patient in addition to the urethra, fever, may also be accompanied by pain in the lower abdomen, hematuria. In general, children with fever, painful urination need to pay attention to, go to the hospital in a timely manner to check, clarify the cause of the disease and then targeted treatment.