Objective：To investigate the immunoregulatory effect of tolerogenic dendritic cells(tolDCs)loaded with hybrid insulin peptides(HIPs)on diabetogenic BDC2.5 T cells. Methods：Bone marrow derived imature DCs(iDCs)of non ⁃obese diabetic(NOD) mice were induced with cytokines，and additional vitamin D3 was added to generate tolDCs. After 24 h stimulation with lipopolysaccharide(LPS)，the supernatants of LPS⁃iDCs and LPS⁃tolDCs were collected to detect cytokines IL⁃12p70 and TGF⁃β，and the phenotype of the above DCs was identified by morphology and flow cytometry. Diabetogenic T cells，namely BDC2.5 CD4+ T cells were incubated with HIPs ⁃ loaded DCs for 3 days，and the proliferation，activation and regulatory T cells(Tregs)production were detected. Results：Phenotypic identification results showed that tolDCs had low expression of costimulatory molecules CD80，CD86， and high expression of coinhibitory molecule PD⁃L1. The phenotype of tolDCs remained stable under the stimulation of LPS，and the secretion of IL⁃12p70 was low while the secretion of TGF⁃β was high compared with LPS⁃iDCs. Both tolDCs and LPS⁃tolDCs loaded with HIPs could inhibit the proliferation and activation of BDC2.5 T cells and induce the production of antigen ⁃ specific Tregs. Conclusion：HIPs loaded tolerogenic dendritic cells can inhibit the proliferation and activation of diabetogenic BDC2.5 T cells and promote the production of Tregs through their stable tolerance phenotype and function.