Many intracellular signaling pathways regulate skeletal muscle differentiation. Among them, PI3K/AKT pathway plays an important role. But the mechanisms of chromatin regulation remain unclear. In this study, the murine C2C12 myoblast cell line was used to investigate the expression of Myogenin and MCK genes during the skeletal muscle differentiation. Western blotting analysis showed that the expression of Myogenin and MCK protein was increased significantly after PI3K/AKT activator treatment for 24 h during the C2C12 cell differentiation and the expression of H3K27me3 demethylase UTX was also increased. Chromatin immunoprecipitation (ChIP) and quantitative PCR (Q-PCR) analysis showed that the enrichment of H3K27me3 on the promoter regions of Myogenin and MCK genes and the enhancer region of MCK gene were decreased. It was opposite to the PI3K/AKT inhibitor treatment. We concluded that the PI3K/AKT pathway maybe regulate skeletal muscle differentiation by regulating the expression of UTX gene to change the enrichment of H3K27me3 on the target genes.