Objective To elucidate the effect of progesterone (Prog) on the cytokine expressions of murine CD11c positive splenic dendritic cells (SDCs). Methods SDCs were purified by immune beads and treated with various concentrations of Prog for 24hours, then cytokine expressions of SDCs in the mRNA level were analyzed through reverse transcription-polymerase chain reaction (RT-PCR). Results Prog increased the transcript of IL-6 in middle dose group but decreased it in high dose, and the level of IL-10 was increased in low and middle dose groups while decreased in high dose group. Furthermore, the transcripts of IL-12 and TNF-α were increased and decreased respectively in all Prog treated groups.Conclusion Prog might regulate organ immune response through influencing cytokine expressions of SDCs. Low- and middle-dose Prog switch organ immune response to Th2-type, while high-dose Prog develops a Th1-type immune response.