The aim of this study was to investigate the role of Delta-like 1 (Dll1) in differentiation and antigen pre-sensation of mouse bone marrow-derived dendritic cells (DCs). In the presence of granulocyte macrophage colony stimulating factor (GM-CSF) and interleukin 4 (IL-4), mouse bone marrow cells were co-cultured with OP9-Dll1 and OP9-GFP cell lines respectively. After 8 days, the immature DCs were stimulated with tumor antigen. The surface molecules of the activated DCs including MHC II, CD80 and CD86 were analyzed by flow cytometry. Levels of IL-12 and IL-10 in the culture supernatant were detected by ELISA. In addition, the proliferation of T-cells co-cultured with DCs was analyzed by FACS through mixed T-lymphocyte reaction. The results showed that compared with OP9-GFP, the bone marrow cells co-cultured with OP9-Dll1 produced significantly more CD11c(+) DCs (p < 0.05), and possessed higher levels of surface molecule expression including MHC II, CD80 and CD86 after tumor antigen stimulation. The DCs secreted higher level of IL-12 (p < 0.05) and less IL-10 (p < 0.01). They also resulted in significantly stronger T-cell proliferation response. It is concluded that Dll1 can promote the differentiation of DCs from mouse bone marrow cells and enhance their antigen presentation capacity.