At present, the effect of exogenous interleukin (IL) -17A in septic mice is still controversial. This study further explored the effect of exogenous IL-17A on multiple organ function and prognosis in septic mice. Mice model of sepsis was established by cecal ligation and puncture (CLP) method, and the mice were randomly divided into 8 groups according to different intervention measures: Sham+PBS, CLP+PBS, CLP+0.25μg IL-17A, CLP+0.5μg IL-17A, CLP+1μg IL-17A, CLP+2μg IL-17A, CLP+4μg IL-17A and CLP+Anti-IL-17A. Survival rates were monitored and recorded at 12-hour intervals, and the expression changes of blood routine, related inflammatory cytokines, liver and kidney function indexes of mice. Pathological injuries of lung, liver and kidney of mice in each group were detected by H&E staining, and the evaluation of bacterial translocation in vitro was performed by inoculation medium. The results showed that except for the sham-operated group, the 7-day survival rate of the mice in the CLP+1μg IL-17A group was the highest (75%). And exogenous administration of appropriate dose of IL-17A was beneficial to reduce alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN) and creatinine (Cre) in septic mice. The pathological damage of lung, liver and kidney tissue also can be alleviated, and the colony count of peripheral blood and spleen tissue of mice were also significantly decreased. From this, we concluded that exogenous administration of appropriate dose of IL-17A can improve the bacterial clearance ability of septic mice, and improve the multiple organ dysfunction and 7-day survival rate of the septic mice.