Objective To investigate the effects of mesenchymal stem cells(MSCs)on the pathological structure and cytokine expression of lung tissue in septic model of diabetic rats. Methods Diabetic rats were ran-domly divided into control,sham-operation,sepsis and MSC-treated groups. The diabetic model was induced by high-sucrose and high-fat diet combined with streptozotocin and cecal ligation and puncture. The pathological changes of lung tissue were observed at 6,12,18 and 24 hours after operation respectively,and the expression of SP-D,TNF-α,IFN-γ and IL-10 in lungs were measured.Results The levels of SP-D,TNF-α and IFN-γ in lung tissue increased gradually with the elongation of time after CLP. The expression of IL-10 in lung tissue increased and then decreased. The trend of MSC intervention increased the content of SP-D,TNF-α and IL-10 in the lung tissue of non-diabetic septic rat model and reduced the content of IFN-γ.MSC intervention reduced the SP-D and TNF-α content.The intervention of MSC had no effect on the content of IFN-γ in the lung tissue of diabetic septic rats.However,it increased and then decreased the content of IL-10.Conclusions The model of sepsis in diabetic rats can be established by feeding combined high-sugar and high-fat diet and streptozotocin combined with cecal ligation and puncture. Mesenchymal stem cells affect sepsis inflammation and organ damage. But its specific role depends on the immune status and the timing of mesenchymal stem cell selection.