Always urinary tract infection in babies cannot be ignored. Urinary tract infection means that pathogens directly invade the urinary tract, grow and multiply in the urine, and invade the mucosa or tissues of the urinary tract and cause damage. Always urinary tract infections are usually accompanied by urinary tract abnormalities, the most common of which is vesicoureteral reflux, which is closely related to renal scarring and reflux nephropathy. Some children with poor renal function are admitted to hospital with renal scarring and poor renal function, and then traced back to their medical history, which is the occurrence of recurrent urinary tract infections, which did not attract the attention of parents and were not actively treated, thus leading to renal scarring, reflux nephropathy and poor renal function. Babies who always have urinary tract infections must be taken seriously and need to be clarified as soon as possible if they have a combination of urinary tract abnormalities, especially vesicoureteral reflux. Special attention should be paid to urinary tract infections in infants, who often do not have irritating symptoms of urinary tract infections, but sometimes just have a fever, or poor mental status, or do not drink milk. So these infants with unexplained fever and poor mental status should always be seen in the hospital and have their urine routine checked for a clear diagnosis.