Abstract: Objective：To observe the intervention effect of bone marrowderived mesenchymal stem cells (BMD-MSCs) on inflammatory factors in lung tissue and plasma of phosgene inhalation lung injury rats. Methods：96 male SD rats were randomly divided into air control group (group A), BMD-MSCs intervention control group (group AM), phosgene exposure group (group PH) and BMD-MSCs intervention group after phosgene exposure (group PM), with 8 rats in each group. Group PH was exposed to dynamic constant phosgene at 8.33 mg/L for 5 min. Group PM was injected with 106 BMD-MSCs via the tail vein immediately after phosgene exposure. The rats in the 4 groups were sacrificed at 6, 24 and 48 h after the models were completed. The lung tissues were taken for pathological examination, lung wet / dry ratio and blood gas analysis. The plasma was taken for the Bio-Plex cytokine test. Results：The level of TNF-α was higher in group PH than group A, and the difference was statistically significant (P＝0.02). The level of TNF-α was lower in the group PM than group PH (P<0.05). The plasma IL-4 concentration in group PM and group PH decreased by 6h and 24 h, which was more significant in group PM (P<0.05). It increased significantly by 48h, which was more significant in group PM (P<0.05). The level of IL-10 was higher in group PM than group PH, and the difference was statistically significant (P<0.05). The level of IL-10 was higher in group PM than group PH, and the difference was statistically significant (P<0.05). Conclusions：Anti-inflammatory cytokines IL-10 and IL-4 were increased and pro-inflammatory cytokines TNF-α was decreased by the tail vein injection of BMD-MSCs, so BMD-MSCs has a protective effect in rats with acute lung injury induced by phosgene.