Objective To understand the current situation of healthcare-associated infection(HAI) in children with hematological tumor, and provide basis for targeted prevention and control measures. Methods A cross-sectional survey was conducted to investigate the infection of patients in the department of hematology oncology of a children's hospital from 2014 to 2018. Results A total of 553 patients with hematological tumor were investigated, the prevalence of HAI ranged from 13.51% to 22.52%, with an average of 18.08%, prevalence of community-associated infection(CAI) ranged from 14.41% to 21.62%, with an average of 18.44%. There were no significant differences between HAI rates and CAI rates of each age group in different years, as well as HAI rates and CAI rates of diffe-rent age groups (all P>0.05); of different types of diseases, HAI prevalence rates in patients with aplastic anemia, acute lymphocytic leukemia, solid tumor, and lymphoma were 34.88% (15/43), 13.53% (28/207), 9.84% (12/122), and 2.27% (1/44) respectively, HAI prevalence rates and CAI prevalence rates in patients with different diseases were both significantly different (χ²=45.54, 18.58, respectively, both P<0.05). Among HAI cases, 33 were other site infection (33.00%), 31 of which had no definite site, but had fever and received effective anti-infection treatment; 22 strains of bacteria and 1 strain of virus were isolated, gram-negative bacteria accounted for 56.52%(13 strains). Conclusion Infection risk of acute leukemia and aplastic anemia is higher than that of solid tumor and lymphoma in children with hematologic tumor, which should be paid more attention. It is necessary to improve the ability of clinical examination, ability of localization and determination of infection, effectively prevent and treat HAI.