ObjectiveTo realize antimicrobial resistance rate of Pseudomonas aeruginosa(P. aeruginosa) and it’s correlation with antimicrobial use density(AUD), and to provide reference for control of healthcareassociated infection.MethodsFrom July 2011 to December 2013, antimicrobial resistance rate of P. aeruginosa isolated from hospitalized patients and AUD of patients were monitored, and the correlation between them was analyzed.ResultsAUD of patients decreased from 73.61 in the third and fourth quarters of 2011 to 41.33 in the same quarters of 2013. Correlation coefficient of AUD and antimicrobial resistance rate of P. aeruginosa was -0.32~0.88, correlation coefficient of resistance rate of P. aeruginosa to aztreonam and aztreonam use density was 0.88,there was statistical significance. ConclusionAUD of hospitalized patients revealed a decreasing tendency, suggesting antimicrobial selective resistance should be considered in clinic.