Abstract： Objective:To explore the risk factors of poor prognosis in patients with acute respiratory distress syndrome (ARDS) treated with extracorporeal membrane oxygenation (ECMO) as an adjuvant therapy.Method:Clinical data of 49 patients diagnosed with ARDS and treated with ECMO from the Respiratory and Critical Care Team of Tangdu Hosptial of Air Force Military Medical University, during January 2018 to March 2024 were collected, including gender, age, Mean arterial pressure, presence of underlying disease, PEEP(positive end-expiratory pressure), white blood cell count, platelets, creatinine, activated partial thromboplastin time, alanine aminotransferase, C-reactive protein, interleukin-6(IL-6), procalcitonin (PCT), ECMO on machine time (days), and tracheal intubation time before ECMO (days), Primary disease of ARDS, Severity of ARDS, Complications related to ECMO patients. Logistic univariate and multivariate regression analysis were used to screen the risk factors of poor prognosis in ARDS patients treated with ECMO.Result:Compared with patients in the survival group, patients in the death group had higher CRP levels (68.67[40.82, 113.92] vs. 19.78[13.39, 41.95], P<0.001), higher PCT levels (4.95[2.44, 7.31] vs. 1.57[0.23, 3.97], P=0.012), longer tracheal intubation time before ECMO (6[4, 12] vs. 3[1, 4], P<0.001), and more patients with ECMO related complications (32.7% vs. 14.3%, P=0.029), with statistically significant differences. Logistic univariate regression analysis showed that CRP (OR=1.030, P=0.003), days of tracheal intubation before ECMO (OR=1.649, P=0.005), and comorbidities related to ECMO (OR=3.657, P=0.033) were closely related to mortality prognosis, and the differences were statistically significant. Logistic multiple regression analysis showed that patients with underlying diseases were associated with ECMO mortality prognosis (OR=5.128, 95CI: 0.751~35.001), but the difference was not statistically significant (P=0.095). CRP levels, pre ECMO tracheal intubation time, and ECMO related complications were significantly correlated with mortality prognosis (OR=1.043, 95%CI: 1.010-1.076), P=0.01; OR=1.691, 95%CI: 1.118~2.557, P=0.013; OR=9.482, 95%CI: 1.150~78.155, P=0.037).