Objective To observe the effects of lung stromal cells on differentiation of mature dendritic cells (mDCs) deriving from mouse bone marrow. Methods The mDCs were cultured by complete medium, half of which was from the lung stromal cell cultures. One week later, the mDCs were induced into regulatory dendritic cells (rDCs). The morphological characteristics of rDCs were observed by Giemasa-Wright stain. The content of cytokines (IL-10 and IL-12p70) in the co-culture supernatants was detected by enzyme-linked immunosorbent assay. The expression level of cellular phenotype was tested with fluorescence-activated cell sorting, compared with mDCs. The difference of rDCs and mDCs was observed. Results Compared with mDCs, rDCs secreted higher level of IL-10 (P＜0.01), and lower level of IL-12p70 (P＜0. 01). In cellular phenotype, the expression of CD11b on rDCs increased (P＜0.01), while the expression of CDllc, Ⅰa and CD86 declined (P＜0.01).Conclusions Lung stromal cells microenvironment may induce the mDCs differentiate into a kind of DC with different biological characteristics.