Objective：To explore the pathogenesis of multiple organ dysfunction syndrome (MODS) with respect to the balance of Th1/Th2. Methods: Eighteen healthy male minipigs, weighing 22-30 kg, were randomly divided into two groups: MODS group and control group. Double-hit method including hemorrhagic shock and endotoxiemia was used to establish the porcine MODS model.The peripheral vein blood samples were collected at different time-points (before bloodletting, before endotoxin injection, 1 h, 24 h,48 h and 72 h after endotoxin injection) in the two groups. The spleen samples were collected after death of the animals. Plasma levels of IFN-γ and IL-4 were detected by enzyme-linked immunosorbent assay (ELISA). Real-time PCR was used to detect the expression of IFN-γ, IL-4, T-bet and GATA-3 mRNA (The latter 2 were the key transcription factors associated with Th1/Th2 response) in the spleen samples.Results: The plasma levels of IFN-γ and IL-4 quickly reached the peak values 1 h after the endotoxin injection, then the level of IFN-γ decreased quickly. The ratio of IFN-γ/IL-4 was significantly lower than the baseline value 72 h after endotoxin injection（P=0.000）. The ratio of IFN-γ/IL-4 mRNA in MODS group was obviously lower than that in the control group（P=0.020）; the ratio of T-bet/GATA-3 was also lower in MODS group（P=0.038）.Conclusion: The shift from Th1 to Th2 occurs in the progress of MODS.