ObjectiveTo investigate health care workers’ (HCWs) understanding on knowledge about central lineassociated bloodstream infection (CLABSI) in intensive care units (ICUs) and operation of CLABSI monitoring system module, so as to provide corresponding basis for evaluation of the monitoring system. MethodsAnonymous selfcompletion questionnaires were used to investigate 54 HCWs who were responsible for the monitoring of CLABSI in the ICUs of 28 hospitals in Beijing.ResultsA total of 54 questionnaires were retrieved, and all were available.  The average working experience of HCWs responsible for CLABSI monitoring was 3 years, 83.33%（n=45）of  HCWs knew the definitions of CLABSI and catheterrelated bloodstream infection（CRBSI）, there were still 14.81% (n=8) of HCWs didn’t know the contents and the difference between CLABSI and CRBSI. 61.11%（n=33）of HCWs still used paper form for recording monitoring data, 33.33%（n=18） adopted spreadsheet+ manual input. 51（94.45%）HCWs understood CLABSI diagnostic criteria, 85% of HCWs knew other symptoms/signs of CLABSI besides high fever and chill. Awareness of CLABSI infection control measurerelated knowledge (intubation technique, standard manipulation, pipeline maintenance, reducing catheterization time, and effective skin disinfection) was 94.45%-100.00%. ConclusionThe CLABSIrelated knowledge and system operation ability of the monitoring personnel should be improved, CLABSI monitoring system module needs to be further evaluated.