Objective To analyze the risk factors of pneumonia in the elderly patients with cerebral infarction and to investigate their impact on its prognosis. Methods A retrospective study was conducted of the clinical data of 275 elderly cerebral infarction patients admitted to the First Affiliated Hospital of Nanjing Medical University from January 2020 to December 2022. The patients were divided into pneumonia group (n=41) and non-pneumonia group (n=234) based on the development of pneumonia after cerebral infarction. The two groups were compared in general information, clinical manifestations, and findings in adjunct tests. SPSS statistics 22.0 was used for data analysis. Depending on the data type, t test or Chi-square test was used for data comparison between two groups. Multivariate logistic regression analysis was conducted to assess the risk factors influencing the occurrence of pneumonia in the elderly patients with cerebral infarction. Results The pneumonia group had higher age, more patients with a history of smoking over 10 years, higher rates in heart failure, atrial fibrillation, myocardial infarction, chronic lung disease, history of stroke, swallowing disorders, consciousness disorders, vomiting, indwelling gastric tubes, invasive tracheal procedures, ventilator-assisted breathing, chest X-ray examination, chest CT examination, brainstem or cerebellar infarction, and higher National Institute of Health stroke scale (NIHSS) scores on admission than the non-pneumonia group, the differences being statistically significant (P<0.05). The pneumonia group were found to have significantly longer hospitalization, higher hospitalization expenses, NIHSS scores after treatment, and mortality rates at one and three months than the non-pneumonia group with statistically significant differences (P<0.05). A 10-year smoking history (OR=3.432,95%CI 1.170-10.065), chronic lung disease (OR=15.580,95%CI 2.744-88.461), dysphagia (OR=2.757,95%CI 1.319-5.760), brain stem or cerebellar infarction (OR=2.036,95%CI 1.282-3.233) and high NIHSS score (OR=1.328,95%CI 1.231-1.434) were independent risk factors of cerebral infarction complicated with pneumonia. Conclusion In the elderly patients with cerebral infarction complicated by pneumonia, special attention should paid to the factors such as smoking history, chronic pulmonary diseases, swallowing disorders, brainstem or cerebellar infarction, and high NIHSS score in order to reduce the occurrence of pneumonia in stroke patients.