Abstract: OBJECTIVE To investigate the risk factors of pulmonary infections in patients with non ST elevation acute coronary syndrome. METHODS A retrospective analysis of 101 patients with non ST elevation acute coronary syndrome from Feb. 2013 to Jan. 2016 was conducted to observe the pulmonary infection rate and analyze the risk factors of pulmonary infections. RESULTS There were 9 cases of pulmonary infections in 101 cases, and the incidence rate was 8.91%. With chronic obstructive pulmonary disease, invasive operation, cardiac function (Killip grade III-IV), left ventricular ejection fraction of 0.4 or less and multi-wall myocardial infarction were risk factors of pulmonary infections (P＜0.05). Chronic obstructive pulmonary disease, invasive operation, cardiac function (Killip grade III-IV), left ventricular ejection fraction of 0.4 or less and multi wall myocardial infarction were independent high-risk factors of pulmonary infections in patients with non ST elevation acute coronary syndrome. CONCLUSION There are many risk factors of pulmonary infections in patients with non ST elevation acute coronary syndrome, so we should carefully assess the individual condition of the patient, formulate corrective measures for prevention of pulmonary infection according to risk factors of the patients, so as to reduce the pulmonary infection rate and improve the prognosis of patients with quality.