This study was to investigate the antimicrobiai resistance of Pseudomonas aeruginosa isolated in 9 consecutive years in a university hospital in China.Disk diffusion test was used to study the antimicrobial resistance.The data were analyzed by WHONET 5 software according to Clinical and Laboratory Standards Institute (CLSI).Most of 2410 strains of P.aeruginosa were collected from sputum 1170 (48.5％),secretions and pus 399 (16.6％),urine 375 (15.6％) during the past 9 years.The antimicrobial resistance ofP.aeruginosa had increased in recent 9 years.The change of the antimicrobial resistance should be investigated in order to direct rational drug usage in the hospital and prevent bacterial strain of drug resistance from being transmitted.