ObjectiveTo investigate the possible causes of surgical site infection（SSI）in neurosurgical patients in a hospital during a short period of time. MethodsMedical 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. ResultsOf 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 environmental 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 Staphylococcus, which was not related with pathogens in infection. Conclusion“The secondary surgery” is the key risk factor for SSI of neurosurgical patients.