Abstract: Objective To analyze risk factors of multiple organ dysfunction syndrome （MODS） secondary to respiratory failure in 210 elderly patients. Methods 210 elderly patients with MODS secondary to respiratory failure who visited The Third People's Hospital of He'nan Province between June 2019 and June 2020 were retrospectively reviewed and set as the experimental group, at the same time, 210 elderly patients with respiratory failure but without secondary MODS were selected as the control group, tended to analyze the risk factors of MODS secondary to respiratory failure in the elderly. Results Among 210 patients with MODS secondary respiratory failure, 112 cases were complicated with heart and renal failure （53.33%）, 45 cases were complicated with liver and renal failure （21.42%）, 25 cases of patients with digestive function failure complicated with liver failure （11.90%）, 20 cases with brain failure complicated with liver failure （9.5%）, 1 patient with pancreatic failure complicated with liver failure （0.47%）, 7 cases with cerebral failure combined with central nervous failure （3.33%）. Aged older than 80, complicated with hypertension, diabetes mellitus hyperlipidemia, chronic hepatitis, carbon dioxide retention, pulmonary fibrosis, smoking index >400/yr, malnutrition, invasive mechanical ventilation, APACHE Ⅱ>15, respiratory acidosis, and metabolic acidosis were independent risk factors for secondary MODS caused by elderly respiratory failure, meanwhile the application of diuretics was the protective factor. Conclusions There are many risk factors influencing secondary MODS caused by respiratory failure in elderly patients. Risk factors should be controlled to reduce the incidence rate of MODS and improve prognosis.