To explore the influencing factors and clinical characteristics of pneumonia in patients infected with influenza A virus. A retrospective study was conducted involving 172 patients admitted to our hospital with influenza A virus infection between January 2023 and March 2025. The patients were categorized into two groups: the pneumonia group, which included 51 patients, and the non-pneumonia group, which included 121 patients, based on the presence or absence of concurrent pneumonia. Logistic regression was employed to analyze independent risk factors for pneumonia in patients infected with the influenza A virus. ROC curves, calibration curves, and decision curves were generated to assess predictive accuracy. The proportion of patients with single type A influenza virus and co-infection with pneumococcus was higher in the pneumonia group compared to the non-pneumonia group（P<0.05）. The clinical characteristics of patients with concurrent pneumonia were primarily characterized by ages 51 to 65, mild conditions, respiratory symptoms, dry rales, and bilateral lung lesions. The logistic multivariable analysis revealed that fever , cough and expectoration, pulmonary rales , time from onset to antiviral treatment ≥ 2days, CRP, and age ≥60 were independent risk factors for the occurrence of pneumonia in patients with influenza A infection. The nomogram model exhibited the highest diagnostic capability for identifying CRP abnormalities. The ROC results indicated that the AUC for the combined prediction was 0.947, with a 95% CI of 0.920 to 0.997. Additionally, the calibration curve demonstrated that this model possesses strong predictive efficacy. Influenza A virus complicated by pneumonia primarily affects individuals aged 31 to 50. The main symptoms include respiratory issues, mild dry rales, and bilateral lung lesions. Key risk factors for patients with influenza A virus infections complicated by pneumonia include fever, cough with sputum production, lung rales, a time interval of two or more days from the onset of symptoms to the initiation of antiviral treatment, elevated CRP levels, and being aged 60 or older. Each of these factors has predictive value for the severity of the condition.