Tumor　vaccines　are　emerging　as　one　of　the　most　promising　therapeutic　strategies　for　cancer　treatment.　With　the　advantages　of　low　toxicity,　convenient　production　and　stable　quality　control,　peptide　vaccines　have　been　widely　used　in　preclinical　and　clinical　trials　involving　various　malignancies.　However,　when　used　alone,　they　still　suffer　from　significant　challenges　including　poor　stability　and　immunogenicity　as　well　as　the　low　delivery　efficiency,　leading　to　limited　therapeutic　success.　Herein,　the　STING-activating　peptide　nanovaccine　based　on　human　serum　albumin　(HSA)　and　biodegradable　MnO2　was　constructed,　which　can　improve　the　stability　and　immunogenicity　of　antigenic　peptides　as　well　as　facilitate　their　uptake　by　dendritic　cells　(DCs).　Meanwhile,　Mn2+　degraded　from　the　nanovaccine　can　activate　the　STING　pathway　and　further　promote　DCs　maturation.　In　this　way,　the　prepared　nanovaccine　can　efficiently　mediate　T-cell　immune　responses,　thereby　exerting　the　effects　of　tumor　prevention　and　therapy.　Moreover,　the　prepared　nanovaccine　possesses　the　advantages　of　low　cost,　convenient　preparation　and　good　biocompatibility,　showing　great　potential　for　practical　applications.