Abstract: In order to explore the effect of exogenous recombinant interleukin 17 a（rIL-17 a） on Staphylocococcus aureus,a mixture of Staphylococcus aureus 923 and rIL-17 a（0.2 μg、0.4 μg、0.6 μg、0.8 μg、1.0 μg） or BSA were inoculated intracutaneously on the back of mice in this experiment. Wound sizes of the inoculation sites in rIL-17 a group and BSA group were measured at different time post inoculation,as well as bacteria counts in blood,inoculation sites,liver,kidney and spleen on 6 days post infection, and the body weights of mice were also calculated. The results showed that the mixture group of Staphylococcus aureus and 0.2 μg rIL-17 a inoculated intracutaneously could very significantly（P＜0.01） and significantly（P＜0.05） reduce wound sizes on day 1 and 3 post inoculation respectively. The mixture group with 1.0 μg rIL-17 a could increase significantly wound sizes of mice on day 3（P＜0.05）. On day 6 post inoculation,0.2 μg and 0.8 μg rIL-17 a groups had very significantly lower counts of Staphylococcus aureus than BSA group in mice blood per mL（P＜0.01）, rIL-17 a group and BSA group had no significant difference of bacteria counts in the inoculation sites（P＞0.05）,0.2 μg rIL-17 a group had very significantly lower bacteria counts than 0.2 μg BSA group in unit weight of liver（P＜0.01）. 1.0 μg rIL-17 a group had very significantly higher bacteria counts than 1.0 μg BSA group in unit weight of liver（P＜0.01）. 1.0 μg rIL-17 a group had significantly lower bacteria counts than 1.0 μg BSA group in unit weight of kidney（P＜0.05）. The rIL-17 a group and BSA group had no significant difference of bacteria counts in unit weight of spleen（P＞0.05）. In fifth and sixth day, 0.2 μg and 0.6 μg rIL-17 a groups could significantly（P＜0.05） and very significantly（P＜0.01）, reduce the inhibitory effect of Staphylococcus aureus on mouce body weights respectively. The results suggested that an appropriate dose of rIL-17 a could be helpful to wound healing at the inoculation site,to the elimination of Staphylococcus aureus from mouse blood and liver,and to the reduction of the inhibition effect of Staphylococcus aureus on mouse body weight. High dose of rIL-17 a could be harmful to bacteria elimination and wound healing,and could be helpful to bacteria survival and wound worsening inversely.