Objective To compare the distribution and antimicrobial resistance of pathogens in non-ventilator hospital-acquired pneumonia (NV-HAP), ventilator-associated pneumonia (VAP) and community-acquired pneumonia (CAP). Methods Medical records of patients with pneumonia in a hospital from October 2017 to September 2019 were retrospectively investigated, according to the definition of NV-HAP, VAP and CAP, patients were divided into NV-HAP group, VAP group and CAP group. Sputum, bronchoalveolar lavage fluid and blood specimens were collected from three groups, difference in constituent and antimicrobial resistance of pathogens of three groups were analyzed. Results A total of 4 391 patients with pneumonia were included, including 1 080 cases in NV-HAP group, 126 in VAP group and 3 185 in CAP group, 841, 191 and 1 440 strains of pathogens were isolated from each group, mostly were Gram-negative bacteria, accounted for 72.77%, 84.82% and 61.18% respectively, difference in distribution of pathogens isolated from three groups was statistically significant (χ²=64.037, P<0.001). Antimicrobial resistance rates of Acinetobacter baumannii to cefepime, cefoperazone/sulbactam, imipenem, gentamicin, tobramycin, levofloxacin, ciprofloxacin and compound sulfamethoxazole, resistance rates of Pseudomonas aeruginosa to cefoperazone/sulbactam and imipenem, as well as resistance rates of Klebsiella pneumoniae to commonly used antimicrobial agents among three groups were all statistically significant (all P<0.05); resistance rates of Staphylococcus aureus to erythromycin, clindamycin and ciprofloxacin in CAP group were all higher than in NV-HAP group (P<0.05). Conclusion NV-HAP, VAP and CAP are different in pathogenic distribution and antimicrobial resis-tance, in the formulation of clinical treatment program, different types of pneumonia should be treated differently.