Vaccine adjuvants play a pivotal role in enhancing immune responses, but traditional adjuvants such as MF59 primarily induce humoral immunity and exhibit limited ability to activate CD8⁺ T cell-mediated cellular immunity. To address this critical gap, we strategically integrated Astragalus polysaccharide (APS), a biocompatible and immunomodulatory traditional Chinese medicine-derived polysaccharide, into the MF59 platform to construct a synergistic nano-adjuvant system (AMF59). This rationally designed adjuvant leverages the complementary properties of both components to enhance dendritic cell (DC) activation, facilitate antigen uptake and cross-presentation, and potently boost CD8⁺ T cell-mediated cellular immunity. In prophylactic tumor challenge studies, the OVA@AMF59 nanovaccine demonstrated potent immunoprotection and significantly suppressed tumor progression. Collectively, this work establishes a rational design strategy for next-generation vaccine adjuvants tailored to applications requiring potent cellular immunity.