Objective: To investigate the effect of progesterone on the expression of NLRP3 and the differentiation of Th17/Treg in murine splenocytes infected by Neisseria gonorrhoeae (Ng). Methods: Murine splenocytes were isolated and in vitro, and randomly divided into five groups: control group, Ng group, Ng+10-9mol/L progesterone group, Ng+10-8mol/L progesterone group, Ng+10-7mol/L progesterone group. The splenocytes were collected after 3 days of culture, the proportions of Th17/Treg cells were detected by intracellular staining using flow cytometry. The mRNA expressions of NLRP3, Th17/Treg specific transcription factors RORγt, Foxp3 in murine splenocytes were detected by real-time PCR. The protein expression levels of NLRP3，RORγt, Foxp3 in murine splenocytes were determined by Western blot. The concentrations of Th17/Treg related cytokines IL-17, TGF-β，IL-10 in the supernatant were detected by ELISA. Results: Under the stimulation of Ng, the proportions of Th17 cells and Treg cells, the mRNA and protein levels of NLRP3, Th17/Treg-specific transcription factors RORγt, Foxp3 in the splenocytes and the concentrations of IL-17, TGF-β, IL-10 in the supernatant increased than those in the controls(P<0.01). After pretreated with progesterone, the proportion of Th17 cells, the mRNA and protein levels of NLRP3, RORγt in the splenocytes and the concentration of IL-17 in the supernatant were significantly lower than those in Ng group. The proportion of Treg cells, the mRNA and protein levels of Foxp3 in the splenocytes and the concentrations of TGF-β, IL-10 in the supernatant were significantly higher than those in Ng group(P<0.01). Conclusion: Progesterone can inhibit the expression of NLRP3 and Th17 differentiation, and promote the differentiation of Treg cells in murine splenocytes induced by Ng infection.