ObjectiveTo understand the distribution and drugresistance of gramnegative bactera isolated from lower respiratory tract in a hospital , so as to provide reference for antiinfection treatment in clinic.MethodsBacteria were isolated from sputum, bronchial aspiration,and pleural effusion of patients  admitted in  a hospital from January 2002 to December 2009, distribution and drug susceptibility test of bacteria  were analysed retrospectively.ResultsA total of 9 884 isolates of bacteria were isolated during 8 years, 6 358 (64.33%) of which were gramnegative bacteria . The main isolated bacteria were Pseudomonas aeruginosa(33.41%), Acinetobacter spp. (20.51%), Klebsiella spp.(19.11%) , and Escherichia coli(12.65%) . The main bacteria of Enterobacteriaceae had low resistance to carbapenems,such as meropenem and imipenem (<3%), and had relative lower resistance to amikacin(17.37%-19.58%), cefoperazone/sulbactam (10.67%-23.62%) , and piperacillin/tazobactam(13.58%-25.11%). The resistant rate of Pseudomonas aeruginosa to  carbapenems was up to 38.54% , and had relatively lower resistance to amikacin(31.50%) and minocycline(32.00%)； Acinetobacter spp. had relatively lower resistance to  carbapenems(10.47%), levofloxacin (24.64%) ,amoxicillin/clavulanic acid (24.33%), cefoperazone/sulbactam (27.00%) ,and minocycline(10.27%).ConclusionGramnegative bacteria are the major pathogens in lower respiratory tract infection  in this area, the main isolated bacteria have a rising resistance to most antimicrobial agents.