Objective：To investigate the effect and mechanism of polyethylenimine （PEI） modified alumina hydroxide nanoparticles（HS/PEI） on enhancing dendritic cell （DC） antigen presentation. Methods：DCs were loaded with HS combined with ovalbum （OVA） antigen in the presence or absence of PEI and co-incubated with B3Z cells. The activation of B3Z cells was determined by CPRG assay. The expression of ubiquitinated OVA protein in DCs was detected by Western blot. After incubated with HS/PEI-OVA and different stimulants（IFN-α，R848），IL-12 expression of DCs was detected by ELISA，and the activation of B3Z cells was determined by CPRG assay after co-incubation with B3Z cells. DCs loaded with HS/PEI-OVA were co-incubated with CFSE-labeled OT-Ⅰ T cells to detect the proliferation of OT-Ⅰ T cells. The increased percentage of CD8+IFN-γ+T cells and IFN-γ secretion of specific T cells induced by DC-HS/PEI-OVA vaccine were examined in B16-OVA tumor-bearing mice. Results：Compared with HS without PEI，HS/PEI significantly enhanced the OVA antigen presentation ability of DCs，increased the ubiquitinated OVA protein expression and IL-12 secretion of DCs. IFN-α and R848 could further enhance the presentation of HS/PEI-OVA by DCs. HS/PEI-OVA could significantly promote OT-Ⅰ T cells proliferation in vitro and induce efficient T-cell responses in vivo. Conclusion：HS/PEI could enhance antigen cross-presentation of DCs and induce efficient T-cell responses.