ObjectiveTo understand multidrugresistant organism (MDRO) healthcareassociated infection(HAI) in patients with malignant tumor, so as to provide basis for making HAI prevention and control measures. MethodsTargeted surveillance method was used to survey MDRO HAI in patients with malignant tumor in a hospital from January 1 to December 31, 2014, WHONET 5. 3 software was used to analyze the data. ResultsA total of 54 056 patients with malignant tumor were surveyed, HAI occurred in 3 542  (6.55%) patients, 847（23.91%）of  which were MDRO HAI. Most patients(54.55%) with MDRO HAI were >60 years old. A total of 2 606 bacterial strains were isolated from patients with HAI, 847 (32.50%) of which were MDROs, and most were extendedspectrum betalactamases (ESBLs)producing Escherichia coli (n=459, 54.19%）. The major site of MDRO HAI was lower respiratory tract (47.34%). The top 3 departments of detection of MDROs were departments of thoracic surgery（17.12%）, colorectal and anal surgery（9.92%）, and general surgery (8.26%). ConclusionIncidence of MDRO HAI is higher in patients with malignant tumor, surveillance of high risk population and monitoring of antimicrobial resistance of pathogens should be strengthened, so as to reduce the occurrence of HAI.