The National Centralized Drug Procurement (NCDP) policy has played a crucial role in China's healthcare reform, aiming to enhance drug affordability and accessibility. This study investigated outpatients' knowledge, attitudes, and practices (KAP) regarding the National Centralized Drug Procurement (NCDP) policy in North China. Conducted from September to November 2024, this cross-sectional study utilized online questionnaires in tertiary hospitals to assess KAP scores among 393 participants, comprising 185 (47.07%) males and 231 (58.78%) who visited outpatient clinics 1-2 times per year. A structured questionnaire was designed based on national policies and expert consultation, covering demographic characteristics, knowledge, attitude, and practice dimensions. The survey was conducted using the Wenjuanxing platform, with strict quality control measures to ensure data accuracy and completeness. Statistical analyses, including Spearman's correlation and structural equation modeling (SEM), were performed to explore the associations between KAP variables. The mean scores were 3.51 ± 3.38 for knowledge (range: 0-12), 22.50 ± 4.31 for attitude (range: 7-35), and 32.48 ± 5.01 for practice (range: 11-55). Significant positive correlations were found between knowledge and attitude (r = 0.266, P < 0.001), knowledge and practice (r = 0.551, P < 0.001), and attitude and practice (r = 0.435, P < 0.001). Structural equation modeling revealed that knowledge directly influenced both attitude (β = -0.304, P = 0.006) and practice (β = 0.602, P = 0.009), with an indirect effect on practice through attitude (β = 0.076, P = 0.009). These findings indicate a structured relationship between knowledge, attitudes, and practices, suggesting that interventions targeting knowledge improvement may have cascading benefits on attitudes and behaviors. Overall, outpatients displayed insufficient knowledge, moderate attitudes, and low engagement with the NCDP policy, emphasizing the need for systematic educational campaigns, improved policy communication, and strategies to enhance patient involvement in decision-making regarding centrally procured medicines.