Objective To investigate the relationship between coagulation indicators and early prognosis in patients with acute respiratory distress syndrome (ARDS).Methods The data of ARDS patients receiving the treatment in the intensive care unit (ICU) from 2008-2019 were selected from the Critical Care Medicine Open Database (MIMIC-Ⅳ V2.0 version) jointly published by MIT,Beth Israel Deaconess Medical Center,and Philips Medical,the data were categorized according to the severity of the patients' disease and the causes of lung damage.The coagulation indexes and 28 d mortality (m28d) rates were compared among different ARDS patients.The receiver operating characteristic (ROC) curve was drawn.The area under the curve was calculated to evaluate the predictive values of the related indicators.The univariate and multivariate logistic re-gression was adopted to analyze the risk factors affecting m28d in the patients with ARDS.Results Maximum prothrombin time (PTmax) in the patients with pulmonary origin ARDS was significantly lower than that in the patients without pulmonary origin ARDS,and the difference was statistically significant (P<0.05).PLTmin,PLTmax and Sequential Organ Failure Assessment (SOFA) score had statistical difference among dif-ferent severity degrees of ARDS patients (P<0.05).Minimum international normalized ratio (INRmin),maxi-mum international normalized ratio (INRmax),minimum prothrombin time (PTmin),PTmax,maximum activated partial thromboplastin time (APTTmax) and SOFA score had statistical differences between the survival group and death group (P<0.05).AUC of INRmin,INRmax,PTmin,PTmax and APTTmax were 0.607,0.624,0.610,0.620 and 0.648 respectively.The multivariate logistic regression analysis showed that APTTmax (OR=1.011,95%CI:1.001-1.022,P=0.029) was an independent risk factor for affecting m28d in the ARDS patients.Conclu-sion Plasma PLT levels in different severities of ARDS patients have the difference and APTTmax on the first day in ICU is an independent risk factor for affecting early prognosis in ARDS patients.