Objective To investigate the relationship between the levels of interferon γ (IFN-γ)/ interleukin-4 (IL-4) and helper T lymphocytes (Th) 1/Th2 in peripheral blood and the prognosis of patients with acute lung injury (ALI) with sepsis. Methods A total of 104 patients with sepsis ALI in our hospital from January 2020 to January 2023 were selected as the study group, 104 patients with simple sepsis during the same period were selected as control group Ⅰ, and 104 healthy subjects were selected as control group Ⅱ. The levels of IFN-γ/IL-4 and Th1/Th2 in peripheral blood of the three groups were compared.The study group was divided into survival patients and death patients according to the prognosis of disease after 28 days of treatment. Analysis of peripheral blood IFN in ALI patients with sepsis- γ/ The correlation between IL-4, Th1/Th2 levels and C-reactive protein, APACHE Ⅱ scores. Univariate and multivariate Logistic regression analysis were conducted to analyze the influencing factors of 28-day survival.The dose-effect relationship between peripheral blood IFN-γ/IL-4 and Th1/Th2 levels and survival at 28 d was analyzed by restricted cubic spines. The value of peripheral blood IFN-γ/IL-4 and Th1/Th2 levels in prognosis was analyzed by receiver operating characteristic curve (ROC curve). Results The levels of peripheral blood IFN-γ, Th1, IFN-γ/IL-4 and Th1/Th2 in study group were lower than those in control group Ⅰ and control group Ⅱ, and the levels of IL-4 and Th2 in control group Ⅰ were higher than those in control group Ⅰ and control group Ⅱ (P＜0.05), and the levels of peripheral blood IFN-γ, Th1, IFN-γ/IL-4 and Th1/Th2 in control group Ⅰ were lower than those in control group Ⅱ, while the levels of IL-4 and Th2 were higher than those of control group Ⅱ (P＜ 0.05). In the study group, the case fatality rate after 28 days was 28.85% (30/104). The levels of IFN-γ, Th1, IFN-γ/IL-4 and Th1/Th2 in peripheral blood of patients who died were lower than those of patients who survived, while the levels of IL-4 and Th2 were higher than those of patients who survived (P＜0.05). The smoking rate, acute physiological and chronic health System Ⅱ (APACHEⅡ) score, arterial blood lactic acid, C-reactive protein and procalcitonin levels in patients with death were higher than those in patients with survival, and the oxygenation index was lower than those in patients with survival (P＜0.05). Peripheral blood IFN- γ/the levels of IL-4 (r=-0.844, P＜0.001) and Th1/Th2 (r=-0.878, P＜0.001) were highly negatively correlated with APACHE Ⅱ score, and peripheral blood IFN- γ/the levels of IL-4 (r=-0.778, P＜0.001) and Th1/Th2 (r=-0.763, P＜0.001) were moderately negatively correlated with C-reactive protein. Arterial lactate and procalcitonin were independent risk factors for 28-day survival in patients with septic ALI, while oxygenation index, IFN-γ/IL-4 and Th1/Th2 were independent protective factors for 28-day survival in patients with septic ALI (P＜0.05).When the level of IFN-γ/IL-4 in peripheral blood was ＜2.5 and Th1/Th2 in peripheral blood was ＜0.43, the risk of death of sepsis ALI patients at 28 days significantly increased. The AUC value of the combined assessment of peripheral blood IFN-γ/IL-4 and Th1/Th2 levels for the survival of patients with sepsis ALI at 28 days was higher than that of peripheral blood IFN-γ/IL-4 (Z=2.215,P=0.027) and Th1/Th2 (Z=1.961, P=0.049) alone.Conclusion The levels of IFN-γ/IL-4 and Th1/Th2 in peripheral blood of patients with sepsis ALI are closely correlated with the prognosis of the disease, and the levels of IFN-γ/IL-4 and Th1/Th2 in peripheral blood are non-linear correlated with the prognosis of the disease. When the peripheral blood IFN-γ/IL-4 level is ＜2.5 and Th1/Th2 level is ＜0.43, it is of high value for clinical evaluation of prognosis