Newborn urinary tract infection, may be the urethra is contaminated, as well as innate physiological characteristics, the body’s immune defense function is imperfect and other reasons. 1. The urethra is contaminated: the urethra of newborns is easily infiltrated by urine or fecal contamination, leading to the invasion of pathogenic bacteria from the urethra to cause urinary tract infections. 2. innate physiological characteristics: especially newborn women, the urethra itself is wide, short and straight easy to induce infection, in addition to newborns ureteral end in the bladder muscle walk short, easy to cause retrograde infection when holding back the urine, is also a factor in newborns urinary tract infection. 3. Immunity defense function is not perfect: the newborn’s own physiological functions are not well developed, the immune defense function may also be imperfectly developed, so it may cause newborn urinary tract infection. Newborn urinary tract infection may have other reasons, need to go to the hospital in time to check, follow the doctor’s instructions for treatment.