Urinary tract infection is a common clinical condition and a frequent disease. Acute urinary tract infections are mostly accompanied by fever, which can mostly improve after antibiotic treatment. If urinary tract infection is always accompanied by fever, it is often accompanied by certain causes, mainly due to urinary tract obstruction or malformation causing fluid accumulation in the kidney and ureter. The most common cause of obstruction is kidney and ureteral stones, especially ureteral stones. Older men with prostate enlargement, chronic urinary retention due to various other causes, and urinary tract malformations such as duplicated kidneys, ureter, and horseshoe kidneys are common, all of which can cause urinary tract infections that are always febrile, especially in patients with diabetes who cannot easily control their fever. Only by removing the cause can the infection be cured and the fever be controlled.