Abstract: OBJECTIVE To investigate and analyze the related risk factors of nosocomial infections in elderly patients with lung cancer after operation, so as to provide theoretical basis for clinical treatment and prevention. METHODS A total of 167 cases of elderly patients with lung cancer after operation in thoracic Department of our hospital from Jan. 2011 to Dec. 2014 were selected as the research subjects. The characteristics and pathogenic bacteria of nosocomial infections with postoperative patients were analyzed, and the related risk factors of nosocomial infection in elderly patients with lung cancer were retrospectively analyzed by single factor and logistic factors. RESULTS In this study, the postoperative associated nosocomial infection rate in the 167 cases of elderly lung cancer patients was 30.54% (51 cases), of which the incidence of lower respiratory tract infection and oral infection were the highest, accounting for 33.33% and 15.69%, and gram-negative bacteria were the main pathogens(60.78%), followed by gram-positive bacteria(29.41%) and fungi(9.80%). Both single factor and multivariate analysis showed that the independent risk factors were the late stage of tumor, invasive operation, combined basic diseases, smoking and anti-tumor therapy(P<0.05). CONCLUSION The independent risk factors affecting nosocomial infections in elderly patients with lung cancer after operation are mainly the late stage of tumor, invasive operation, combined basic diseases, smoking and anti tumor therapy, so the control of basic diseases and primary cause of diseases should be strengthened to reduce the invasive operation, timely isolation and related nutritional support, in order to reduce the incidence of nosocomial infections of elderly patients with lung cancer.