ObjectiveTo investigate the effect of preoperative chlorhexidine bath for reducing the incidence of surgical site infection(SSI) in patients undergoing spinal surgery.MethodsAll patients who undergoing spinal surgery (with no implants) in the department of neurosurgery of a hospital between January 2013 and December 2014  were monitored, the selected patients were divided into control group (JanuaryDecember of 2013, no intervention measures were taken) and trial group(JanuaryDecember of 2014, 1.8%-2.2% chlorhexidine bath for two nights before operation), incidence of  SSI between two groups of patients before and after intervention was compared, interventions effect was evaluated.ResultsA total of 1 043 patients undergoing spinal surgery were enrolled, 41(3.93%) had SSI， incidence of SSI  rates in control group and trial group were 6.47% and 2.34% respectively， the difference was statistically significant (P=0.001). According to the incidence of SSI in control group, actual infected patients in  trial group were 27 less than the anticipated patients with infection.The average hospitalization expense in SSI group and nonSSI group were ￥33 641.00 and ￥23 072.50 respectively，each patient could save  ￥10 568.50 on average. Therefore, through the intervention measures, ￥285 349.50 of hospitalization expense could be saved. Except ￥2 100 of trial material cost and ￥12 820 of manual labour cost, ￥270 429.50 of social cost was ultimately saved. The mean length of hospital stay in control group and trial group were 10 (8-12) days  and 9 (8-12) days respectively，rank test showed that the difference was not statistically significant（Z=-0.68，P=0.50）.ConclusionChlorhexidine bath intervention can not only reduce SSI rate， but also save the expense of hospitalization, whether it can shorten the length of hospital stay needs to be further studied.