The relationship between dendritic cells (DCs) and L-selectin in the progress of atherosclerosis is unclear. Here, we used L-selectin co-cultured with DCs to investigate the effect of L-selectin on the maturation of DCs in vitro. Monocytes derived DCs were isolated and cultured from human peripheral blood. After being stimulated with L-selectin and/or its antagonist for 24-48 hours, the feather of cells was observed by the electron microscope. The expression of mature antigens CD1a, CD80, CD83, and CD86 were investigated by flow cytometric analysis (FACS). RT-PCR and FACS were used to detect the mRNA and protein expression of Toll-like receptor 4(TLR-4). We found that only the cells of giving L-selectin have the mature special feature for irregular shapes. DCs which were stimulated by L-selectin have a larger number of expressing CD1a, CD80, CD83, and CD86 compared with non-stimulated and cultured with L-selectin antagonist. The transcript levels of TLR4 were significantly higher after L-selectin and lipopolysaccharide (LPS) stimulated. And the antagonist of L-selectin can deeply decrease the expression of CD1a, CD80, CD83, and CD86 on DCs appeared to coincide with the level of TLR4 transcription. The results demonstrate L-selectin can promote the maturation of DCs via up-regulation the expression of TLR4.