Objective:To investigate the risk factors of acute lung injury (ALI) caused by Staphylococcus aureus infection, and to construct a risk warning model. Methods:Patients with Staphylococcus aureus infection confirmed by sputum or blood culture admitted to the Affiliated Hospital of Jiangnan University from January 1, 2020 to May 10, 2022 were enrolled and divided into ALI group and non-ALI group. The age, smoking status, C-reactive protein (CRP), procalcitonin (PCT), neutrophil-to-lymphocyte ratio (NLR), albumin, oxygenation index and other clinical data were compared between the two groups. Univariate analysis was performed by using independent sample t test and chi-square test. Binary logistic regression analysis was used to screen the independent risk factors of ALI caused by Staphylococcus aureus infection, and a risk warning model was constructed. The receiver operator characteristic (ROC) curve was used to evaluate the predictive ability of the model. Results:There were 96 cases of Staphylococcus aureus infection, including 68 cases (70.8%) in ALI group, of which 41 cases (60.3%) were positive in sputum culture and 27 cases (39.7%) were positive in blood culture. Compared with the non-ALI group, the proportion of patients aged ≥60 years in ALI group was lower (58.8%(40/68) vs 64.3%(18/28)), the proportion of smoking was higher (58.8%(40/68) vs 35.7%(10/28)), and the differences were both statistically significant ( χ2=0.76 and 0.03, respectively, both P<0.05). The levels of CRP, PCT and NLR in the ALI group were all higher than those in non-ALI group, while oxygenation index and albumin level were both lower, and the differences were all statistically significant ( t=-5.28, -3.46, -9.87, 12.83 and 3.08, respectively, all P<0.05). Binary logistic regression analysis showed that CRP (odds ratio ( OR)=1.973, 95% confidence interval (95% CI) 0.956 to 2.989), PCT ( OR=3.734, 95% CI 1.014 to 13.746), NLR ( OR=1.152, 95% CI 1.058 to 2.254) and albumin ( OR=1.527, 95% CI 1.110 to 2.102) were independent risk factors for ALI caused by Staphylococcus aureus infection. The areas under the ROC curve of CRP, PCT, NLR, albumin and the risk warning model constructed from the combination of four risk factors were 0.69, 0.81, 0.83, 0.78 and 0.93, respectively. The sensitivities were 65.14%, 89.91%, 84.40%, 56.88% and 98.17%, respectively. The specificities were 62.37%, 60.22%, 65.59%, 80.64% and 93.55%, respectively. The accuracy of the effectiveness test of the risk warning model was 84.97%. Conclusions:CRP, PCT, NLR and albumin are the independent risk factors for ALI caused by Staphylococcus aureus infection. The risk warning model based on the above factors has a good early warning effect on ALI caused by Staphylococcus aureus infection.