Objective: To analysis distribution and resistance of Pathogenic Bacteria in senile patients from lower respiratory tract infection and provide reference for rational use of antibiotics in clinics .Methods: To collect phlegm specimens from lower respiratory tract infection in elder patients from Jan 2007 to Dec 2011 in our department. Bacterial culture performed referring to National Guide to Clinical Laboratory Procedures. ATB Expression system (France, Biomerieux) was used to identify the strains. The results of examination were judged according to CLSI standard. Results: 41.6% positive pathogenic bacteria were isolated from 1520 strains and mixed infective rate was 25.73%. The rate of gram-negative bacteria, gram-positive cocci and fungi accounted for 68.25%、21.32% and 10.4% in 633 isolated strains, respectively. The top 5 of isolated bacteria were Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Acinetobacter baumannii. MRSA accounted for 75.7% of Staphylococcus aureus and there were not found about resistant gram-positive cocii to Vancomycin, Teicoplanin and linezolid. Among gram-negative bacteria， lowest resistant rate was carbapenems（14.７%～34.2%）, and secondly, Cefepime, Piperacillin / tazobactam, cefoperazone / sulbactam and amikacin, etc. The drug-resistence was higher including Ampicillin and third generation Cephalosporins (eg, Cefuroxime, Cefazolin, Cefotaxime. Conclusion: The bacteria from lower respiratory tract infection in elderly patients were distributed extensively and there was severe resistance to antimicrobials. It is necessary to strengthen monitoring bacteria and using rationally antibiotics and slowing down drug-resistence.