This study aims to analyze differences in HPLC fingerprints andin vitroantioxidant activity of different processed Notoginseng Radix et Rhizoma (NRR),and to investigate their spectrum-effect relationships.HPLC was used to establish fingerprints of 36 batches of different processed NRR,steamed Notoginseng Radix et Rhizoma (SNRR),fried Notoginseng Radix et Rhizoma (FNRR),and major characteristic peaks were analyzed by HPLC-Q-TOF-MS.Principal component analysis(PCA),hierarchical cluster analysis (HCA),and partial least squares regression analysis (PLSR) were employed for quality evaluation and screening for differential markers.Antioxidant activity was assessed by DPPH radical scavenging capacity,FRAP total antioxidant capacity,and ABTS radical scavenging assays.PLSR and Pearson correlation analysis were applied to explore the spectrum-effect relationships between chemical components and antioxidant activity.A total of 37 major characteristic peaks were matched in the HPLC fingerprints of 36 batches of different processed NRR,and 33 of these peaks were identified.PCA,HCA,and PLSR classified NRR into three groups,and PLSR screened out 13 differential components.Antioxidant effects of NRR were significantly enhanced after processed,with the following order:FNRR＞SNRR＞NRR.PLSR and Pearson correlation analysis identified six characteristic peaks strongly associated with antioxidant activity,including maltotriose,ginsenosides Rh₄,F₂,Rg₂,Rk₁,and Rg₅.This study established a quality evaluation model for different processed NRR based on chemical composition and antioxidant activity,providing a reference for elucidating its active antioxidant components and quality control.