ObjectiveTo investigate the prevalence rates of healthcareassociated infection (HAI) and antimicrobial use in a psychiatric hospital. MethodsThe annual crosssectional survey on HAI among all hospitalized psychiatric patients from 0:00 to 24:00 of June 20, 2012-2015 were conducted, HAI during 4 years were analyzed. ResultsA total of 2 584 hospitalized patients were surveyed, 47 patients had 48 episodes of HAI， the prevalence rate and case prevalence rate of HAI were 1.82% and 1.86% respectively；prevalence rates in 2012-2015 were 2.09%, 1.56%, 1.48%, and 2.11% respectively（χ2=1.23, P=0.75）. The top three departments of high prevalence rates were male section of medical rescue department（3.80%）, male section of acute intervention department（3.31%）, and department of geriatric psychiatry（2.78%）. The top three infection sites were upper respiratory tract (31.91%), lower respiratory tract (29.79%), and gastrointestinal tract(14.89%); 28 strains of pathogenic bacteria were detected, the top three pathogens were Escherichia coli (28.58%), Klebsiella pneumoniae (17.86%), and Staphylococcus aureus (14.29%); antimicrobial use rates in 2012-2015 were 10.91%, 5.78%, 5.41%, and 5.06% respectively, which decreased year by year（χ2=23.13，P＜0.01）. ConclusionPrevalence rates of HAI in four consecutive years maintained a low level in this hospital, antimicrobial usage rates decreased year by year.