Abstract: OBJECTIVE To investigate the epidemiological characteristics of health care-associated infections (HAIs) in hospitalized patients of neurosurgery department of a large scale three-A general hospital in Beijing and analyze the variation trend over a long time period. METHODS The data were collected from all of the patients who were hospitalized in neurosurgery department from Jan. 2015 to Dec. 2024 by real-time HAIs monitoring system. Taken the outbreak of COVID-19 epidemic and comprehensive upgrading of infection control system as the turning point, a ten-year period was divided into the conventional infection control period (from 2015 to 2019) and the intensified infection control period (from 2020 to 2024). A descriptive analysis was performed for the infection rate, case-time infection rate, baseline information of patients with infections, infection sites and pathogens. RESULTS A total of 45 002 patients who were hospitalized in the neurosurgery department from Jan. 2015 to Dec. 2024 were enrolled in the study, and 2 464 patients (2 905 case-times) had HAIs, with the average infection rate 5.48%, the average case-time infection rate 6.46%; the infection rate exhibited a downward trend during the 10-year time period(Z=-6.462, P＜0.001). The incidence rate of HAIs of the neurosurgery department patients was 4.90% in the intensified infection control period, lower than 6.17% in the conventional infection control period (χ²=34.665,P＜0.001). Among the patients with HAIs, the patients with surgical site infection accounted for 48.54% (1 410 cases), the patients with lower respiratory tract infections 32.19% (935 cases), the patients with urinary tract infections 7.71% (224 cases). Totally 2330 strains of pathogens were isolated, of which 1 100 (47.21%) were gram-negative bacteria, and Acinetobacter baumannii (317 strains) was the predominant species, accounting for 13.61%. CONCLUSIONS The prevalence rate of HAIs shows a downward trend among the hospitalized patents of neurosurgery department in the ten years of time period, and the infection rate also shows a downward trend in the care unit. The remarkable decline during the intensified infection control period is associated with the transition of infection control system from element construction to refined management of link quality as well as the measures intensified during the epidemic period.