ObjectiveTo understand department distribution, pathogens, and antimicrobial resistance of postoperative lower respiratory tract infection(LRTI), provide evidence for formulating prevention and treatment measures. MethodsFrom March 15, 2016 to December 31, 2016, monitored data of LRTI in the crosssectional survey of National Healthcareassociated Infection Surveillance Network(NHAISN) were collected and analyzed. ResultsA total of 1 057 361 hospitalized patients in 1 588 hospitals were surveyed, 12 827 cases of LRTI occurred, 2 275 of which were postoperative LRTI, accounting for 17.74% of LRTI. Most LRTI occurred in patients in surgery departments (n=1 700 cases, 74.73%), followed by general intensive care unit (n=372 cases, 16.35%); among departments of surgery, prevalence rate of LRTI was highest in patients in department of neurosurgery (2.34%), followed by department of thoracic surgery (1.71%). A total of 1 163 strains of pathogens were isolated, gramnegative bacteria accounted for 83.66%; the top 5 pathogens were Pseudomonas aeruginosa (20.29%), Klebsiella pneumoniae (19.69%), Acinetobacter baumannii (19.69%), Escherichia coli (6.53%), and Staphylococcus aureus (5.85%). Among pathogens causing postoperative LRTI, isolation rates of methicillinresistant Staphylococcus aureus, imipenem/meropenemresistant Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii were 64.15%, 8.00%, 14.19%, 29.14%, and 62.58% respectively, isolation rate in nonoperative LRTI infection were 76.03%, 8.85%, 15.51%, 39.67%, and 70.13% respectively; resistance rate of Pseudomonas aeruginosa to imipenem/meropenem and Acinetobacter baumannii to cefoperazone/sulbactam were both higher in postoperative LRTI than in nonpostoperative LRTI(the latter were 47.17% vs 63.68%), difference were both significant(both P<0.05). ConclusionIncidence of postoperative LRTI is highest in department of neurosurgery, gramnegative bacteria are the predominant pathogens, resistance of pathogens is serious, but antimicrobial resistance in partial strains are lower than nonpostoperative LRTI.