Abstract: OBJECTIV To investigate the clinical symptoms and immune function of chronic heart failure patients with pulmonary infections and explore the drug resistance of isolated pathogenic bacteria. METHODS A total of 280 patients with chronic heart failure who were treated in the hospital from Jun 2015 to Jun 2016 were enrolled in the study and divided into the observation group with 124 cases and the control group with 156 cases according to the status whether the pulmonary infections occurred during the hospital stay. The baseline data of the two groups of patients were analyzed, the clinical manifestations of the patients complicated with pulmonary infections and the related factors for the infections were observed, the T lymphocyte subsets and serum immunoglobulin levels were compared between the two groups of patients, the drug resistance of the pathogens and prognosis of the two groups of patients were observed, and the risk factors for the pulmonary infection were analyzed. RESULTS There was significant difference in the length of hospital stay or history of diabetic mellitus between the two groups of patients (P<0.05). There were 58 (46.77%) chronic heart failure patients who had typical respiratory system symptoms such as cough, fever, chest pain after they had the pulmonary infections. The result of sputum culture indicated that totally 108 strains of pathogenic bacteria were isolated from 124 patients, of which 48.15% were gram-negative bacteria, 30.56% were gram-positive bacteria, and 21.29% (23 strains) were fungi. The analysis of immune function of the two groups of patients showed that there was significant difference in the CD₈⁺, CD₄⁺/CD₈⁺, IgG, or IgM level between the two groups of patients (P<0.05); there was no significant difference in the CD₄⁺ or IgA level between the two groups of patients. As compared with the factors for the pulmonary infections, there was significant difference in the mean NYHA classification, invasive examination or treatment, antacids, or prophylactic use of antibiotics between the two groups of patients (P<0.05). CONCLUSION The patients with chronic heart failure tend to have pulmonary infections and present with a variety of clinical symptoms, and the composition of the pathogens is complex. It is necessary to reasonably use antibiotics based on the result of drug susceptibility testing so as to control and prevent nosocomial infections.