Specific neoantigens are promising candidates for personalized cancer vaccines and immunotherapies, whereas the low immunogenicity and physicochemical variability are the main challenges in clinical trials. Herein, based on the rational design of neoantigens, we developed biepitope nanovaccines via integrating CD4+ with CD8+ T cell epitopes. A class of amphiphilic peptides composed of biepitope and hydrophilic amino acids can form well-defined nanostructures, thus incorporating functional sequences into an artificial platform. Cellular uptake studies demonstrated the enhanced endocytosis of biepitope neoantigens in dendritic cells (DCs). Such designed biepitopes can further stimulate the maturation of DCs, as validated by the upregulation of costimulatory molecules and secreted proinflammatory cytokines, which show the potential ability to prime T cells and evoke specific cellular immunity. The inspiring prophylactic and therapeutic efficacy of biepitope nanovaccines was evaluated in murine colon cancer. In contrast to individual CD8+ T cell epitopes, the rationally designed biepitope nanovaccines can efficiently provoke immune activation and potentiate antitumor immunity both in vitro and in vivo, presenting an alternative strategy for neoantigen vaccines.