Objective To explore the effectiveness of antimicrobial stewardship (AMS) in reducing antimicrobial use density (AUD) in children. Methods An AMS team was established to analyze the causes for high AUD in a tertiary first-class children's hospital. With the target of an AUD ≤20 defined daily doses (DDDs) in this hospital, comprehensive improvement strategy was proposed based on the current situation. Relevant indicators of antimicrobial agents in this hospital before and after AMS improvement were compared, and the effectiveness was analyzed. Results AUD in this hospital gradually decreased from 24.83 DDDs in 2021 to 19.06 DDDs in 2022, with 21 out of 23 departments decreased. Microbial examination rate before therapeutic antimicrobial use increased from 82.01% to 89.09%, and antimicrobial use rate decreased from 45.74% to 43.63%. Antimicrobial prophylactic use rate in class Ⅰ incision decreased from 27.21% to 24.18%, the incidence of healthcare-associated infection decreased from 3.18% to 2.66%, and the detection rate of multidrug-resistant organisms decreased from 12.45% to 10.99%, while the incidence of class Ⅰ incision infection remained unchanged. Conclusion Antimicrobial management system centered on AMS is effective in promoting the rational application of antimicrobial agents in pediatric specialty hospitals.