ObjectiveTo evaluate  drug resistance and risk factors of pandrug resistance of Pseudomonas aeruginosa (PDRPA)  isolated from clinical specimens in a hospital.MethodsFive hundred and thirtyeight strains of Pseudomonas aeruginosa(PA) were isolated from a hospital between January 1st,2008 and May 1st, 2009, the results of susceptibility test of PA to 18 kinds of antimicrobial agents were analyzed  retrospectively. The clinical data of patients with  PDRPA infections (PDRPA infection  group,28 cases) were compared with that of patients without PDRPA infections( control group, 48 cases) during the same hospitalization period. ResultsAmong 538 strains of nonrepeated PA, resistance to amikacin and piperacillin/tazobactam was low, which was 18.40% and 27.70% respectively; resistance to imipenem, meropenem, ceftazidime and ciprofloxacin  was 69.52%, 56.88%, 45.91% and 56.88% respectively.28 (5.20%) strains was PDRPA.  Risk factors for PDRPA infections were tracheal intubation, long time hosptalization in ICU and longterm combination of  antimicrobial application. ConclusionDrugresistant rates of PA to multiple antimicrobial agents  are  very high, especially resistance to imipenem,which should be paid attention to. Patients hospitalized in ICU and using multiple antimicrobial agents, especially those with mechanical ventilation, should be paid attention to PDRPA infection.