Objective To construct a novel carrier-free nanovaccine to trigger a strong anti-tumor immune effect in the body. Methods The Toll-like receptor 4 agonist monophosphoryl lipid A (MPLA) was covalently conjugated with mucin 1 (MUC1)-targeting amino acid motif (Maa) to form MPLA-Maa monomer molecules.Subsequently,MPLA-Maa was self-assembled with Leu-His modified MUC1 polypeptide (LMP) to construct the nanovaccine system (MAP NVs). Results MAP NVs exhibited a particle size of (169.85±4.05) nm,a polydispersity index of 0.308±0.021,and the Zeta potential of (-19.10±1.00) mV,and remained stable in vitro for over 10 days.Cell experiments showed that the nanovaccine significantly promoted dendritic cell maturation and activation and promoted tumor necrosis factor-α secretion.In the B16-MUC1 melanoma model,MAP NVs demonstrated remarkable antitumor effects,significantly inhibiting tumor growth and prolonging the survival of tumor-bearing mice.Mechanism analysis further revealed that MAP NVs effectively activated T cell immune response,promoted the proliferation of CD4⁺ and CD8⁺ T cells,and induced the production of CD8⁺ central memory T cells.After antigen restimulation,the secretion levels of tumor necrosis factor-α and interferon-γ were significantly elevated,which indicated long-lasting immune memory. Conclusions A carrier-free spherical peptide nanovaccine based on the co-delivery strategy of MPLA and LMP was successfully constructed.By promoting dendritic cell activation and enhancing T cell immune response,this system exhibits significant antitumor activity and long-lasting immune memory effect.This study provides a new technical approach and an experimental basis for developing nanovaccines against tumors.