Objective To analyze the risk factors affecting the prognosis of patients with severe pneumonia complicated with moderate-to-severe acute respiratory distress syndrome (ARDS) in intensive care unit (ICU). Methods The clinical data of 76 patients with severe pneumonia complicated with moderate-to-severe ARDS were retrospectively analyzed. According to Glasgow clinical outcome score at discharge, they were divided into good prognosis group (n=47) and poor prognosis group (n=29). Logistic regression was used to analyze independent risk factors for prognosis quality in patients with severe pneumonia complicated with moderate-to-severe ARDS. Results Age, mechanical ventilation time, ARDS indexing, ICU stay, acute physiology and chronic health evaluation II (APACHE II score) and sequential organ failure assessment (SOFA) score were single factors for poor prognosis of patients with severe pneumonia complicated with moderate-to-severe ARDS (all P<0.05). Advanced age, severe ARDS, short ICU stay, short mechanical ventilation time and increase of APACHE II score and SOFA score were independent risk factors for poor prognosis in patients with severe pneumonia complicated with moderate-to-severe ARDS (all P<0.05). Conclusion The prognosis of patients with severe pneumonia complicated with moderate-to-severe ARDS is related to age, mechanical ventilation time, ARDS indexing, ICU stay, APACHE II score and SOFA score.