Objective  To investigate the relevant mechanisms of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/FoxO1 and interleukin-17(IL-17) in the oneset of experimental autoimmune encephalomyelitis(EAE) mice.    Methods   Sixty C57BL/6 mice were randomly divided into control group and model group (EAE)， 30 in each group. The EAE model was induced by myelin oligodendrocyte glycoprotein (MOG_35-55) together with complete Freund’s adjuvant. The behavioral score of each group was observed. The spinal cord，spleen and peripheral blood were obtained when the behavioral score was 4. IL-17 and interferon-γ (IFN-γ) contents in mouse serum and supernatant of splenocytes stimulated with a-CD3 and MOG_35-55，respectively，in vitro for 7 days were detected by ELISA. The percentage of CD4+IL-17+ cells in the mouse spleen was monitored via flow cytometry. The expressions of IL-17 and PI3K/Akt/FoxO1 in the spinal cord were detected by Western blotting.    Results Compared with the control group, the behavioral score of the EAE group was significantly higher than that of the control group. HE staining and Luxol fast blue staining indicated that EAE spinal cord increased prominently inflammatory infiltration and demyelination(P<0.05). IL-17 and IFN-γ contents of the EAE group in serum and supernatant of splenocytes cultured in vitro increased remarkably(P<0.05). The percentage of  CD4+IL-17+ T cells in splenocytes also increased markedly(P<0.05). The protein levels of IL-17 and phosphorylated Akt (p-Akt)in the spinal cord of the EAE group increased observably，while that of phosphorylated FoxO1 (p-FoxO1)decreased significantly(P<0.05).   Conclusion  The increased secretion of proinflammatory factor IL-17 in the spinal cord of the EAE group may be related to the activation of the PI3K/Akt/FoxO1 signaling pathway and T-cell function.