Objective: To retrospectively analyze the drug resistance trend of bacteria detected in bacterial pneumonia, and to provide a basis for improving the prevention and control level of nosocomial infection. Methods:The case data and sputum culture results of 565 patients with bacterial pneumonia in different age groups were collected. The bacterial detection rate was calculated and the drug sensitivity results were analyzed. Results:A total of 565 patients with bacterial pneumonia were included, including 99 young people aged 18-44 years and 466 middle-aged and elderly people aged 45-101 years. Among them, the detection rate of bacteria in young people aged 18-44 years was 7.1%, mainly Proteus mirabilis, Acinetobacter baumannii and Streptococcus pneumoniae. The multi-drug resistant bacteria were mainly Acinetobacter baumannii, but the proportion of multi-drug resistant strains was only 42.9%. The detection rate of bacteria in middle-aged and elderly people aged 45-101 years old was 22.1%, which was significantly higher than that in young people with bacterial pneumonia, and the bacteria showed diversity, including Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, etc. Among them, multidrug-resistant bacteria accounted for 49.5%. Common pathogens of bacterial pneumonia included Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, Staphylococcus aureus, etc. Conclusion: The detection rate of bacterial pneumonia in middle-aged and elderly people is higher than that in young people, and the incidence of multidrug resistance is high, mainly gram-negative bacteria.