Pancreatic cancer is characterized as a type of gastrointestinal tumor with a poor prognosis and high degree of malignancy. CIITA gene was found highly methylated in pancreatic carcinoma cell line PANC-1 and responsible for the low expression of major histocompatability complex II (MHC-II) that may lead to immune evasion. Here, we prepared pancreatic cancer vaccine with PANC-1 cells via epigenetic modification to enhance the MHC-II expression. Then the vaccine was injected into C57BL/6J mice and the effect was examined. Our study found that the vaccine could promote the proliferation of antigen-specific T cells, enhance the killing activity of cytotoxic T lymphocytes (CTLs), promote Th1-type cell-mediated secretion of cytokines IFN-γ and IL-2 while inhibiting Th2-type cell-mediated secretion of IL-4, and inhibit the secretion of TGF-β. Generally, the epigenetically modified vaccine could enhance the body's antitumor immune response, providing feasibility research on cancer vaccine for therapy of pancreatic cancer.