Among Urinary calculi, the higher rates of infection stone resulted in a higher incidence of postoperative urinary tract infection. The conventional postoperative prophylaxis medicine was the use of antimicrobial drugs half an hour before surgery.Foreign studies had shown that continuous preoperative one week use of nitrofurantoin can significantly reduce the incidence of urinary sepsis. So the investigators assume that preoperative extended use time of prophylaxis antibiotic may reduce the incidence of urinary tract infection or urinary sepsis.