Abstract: Objective To analyze the prevalence of self-medication and prescribed antibiotic use for acute respiratory infections (ARI) among children under 5 years old in Eastern and Western China, to identify the determinants of these behaviors, and to provide evidence-based references for developing effective antimicrobial resistance (AMR) intervention strategies. Methods Based on a cross-sectional study design and a multi-stage stratified random sampling method, face-to-face questionnaire surveys were conducted with guardians of children aged 0-5 years in Taizhou and Huzhou (Zhejiang Province) and Haidong (Qinghai Province). The study investigated the patterns of self-medicated and prescribed antibiotic use during ARI episodes during the winter and spring of 2024-2025. Multivariable logistic regression models were employed to analyze the influencing factors. Results A total of 2,063 valid questionnaires were collected. The overall antibiotic use rate among children with ARI during the 2024-2025 winter-spring period was 42.90%; specifically, 77.51% (n=686) of the children obtained antibiotics via physician prescriptions, while 37.29% (n=330) received home-based self-medication. β-lactams and macrolides were the most commonly used antibiotic classes. Multivariate analysis indicates that compared with Haidong, parents of pediatric patients in Taizhou City are significantly less likely to use antibiotics at home for self-treatment(OR=0.485, 95% CI: 0.320-0.731, P < 0.001). Older child age, non-local household registration, and higher parental education and household income were associated with an increased risk of self-medication with antibiotics at home (P < 0.05). Additionally, older child age, prior self-medication with antibiotics at home, and undergoing laboratory or imaging examinations during the medical visit were associated with an elevated risk of receiving an antibiotic prescription (P < 0.05). Household income and parental education did not show statistical significance in the prescription model. Conclusion The overall antibiotic use rate for childhood ARI in China remains high, characterized by a significant East-West regional divergence. There is a notable homogeneity in the classes of antibiotics used for both selfmedication and prescriptions, with β-lactams and macrolides being the most prevalent. It is recommended to implement stratified and targeted antibiotic stewardship strategies: community interventions should focus on regulating illegal over-the-counter sales in pharmacies and correcting parental misconceptions, while hospital-level interventions should prioritize standardizing clinical pathways to limit over-prescription.