Objective To investigate the possible causes of surgical site infection(SSI)in neurosurgical patients in a hospital during a short period of time.Methods Medical data of 135 neurosurgical operative patients from February 1 to March 15,2013 were reviewed,the possible risk factors for SSI were analyzed retrospectively with case-control study.Results Of 135 operative neurosurgical patients,5 (3.70%)developed SSI.Case-control study showed that the ratio of the run of the fifth operating room and undergoing of secondary operation was 4.07 (95%CI :0.52 -36.65)and 18.00(95%CI :2.00 -180.00)respectively.The difference between each surgeon special SSI rate and the average SSI rate in 2012 (2.54%[17/669])was not significantly different (P >0.05).Bacterial detection of en-vironmental specimens of the fifth operating room showed that except anesthetic cuff exceeded standard,the others were met the national requirements,and the isolated bacteria from anesthetic cuff was coagulase negative Staphylo-coccus ,which was not related with pathogens in infection.Conclusion “The secondary surgery”is the key risk fac-tor for SSI of neurosurgical patients.