OBJECTIVE For the reasonable use of antibacterial drugs, drug resisitance diversity of Pseudomonas aeruginosa was studied in our hospital. METHODS Antibacterial activity to all P. aeruginosa collected in four years from 2004 to 2007 were determined by K-B test, and data were analyzed by WHONET software. RESULTS The resistance rate to ampicllin, cefazolin and cefoteton were 100.0%, but low to ceftrazidime, cefoperazone and cefoperazone/sulbactam(3.2% in 2007). The resistance rate to levofloxacin increased year by year, while that to ciprofloxacin descreased from 15.6% to 9.6%.The resistance rate to gentamicin and amikacin descreased from 20.0% to 16.4%,and from 11.1% to 4.8%, respectively. The resistance rate to imipenem and meropenem accounted for about 10.0%, which was as same as ceftazidine. CONCLUSIONS The resistance of P. aeruginosa in our hospital is stable. Clinician should choose right antibacterial drugs on the basis of the test for antibacterial sensitivity and the pharmacological characteristis to improve curative effect and decrease the resistance of bacteria.