This research aims to study the total anthraquinone content and total polyphenol content of 20 batches of rhubarb palm decoction pieces,and to preliminarily analyze the spectrum-effect relationship of antioxidant activity in vitro.The total anthraquinone content of rhubarb was determined by HPLC,the total polyphenol content was determined by UV spectrophotometry,DPPH and ABTS methods were used to evaluate the antioxidant activity of rhubarb in vitro.HPLC fingerprint was used to take the common peak as the research object,and cluster analysis,principal component analysis,partial least square analysis,gray correlation analysis and Pearson correlation coefficient method were used to analyze the antioxidant activity.The change of chromatographic peak area before and after the reaction was used as the supplement of spectral analysis.The results showed that the total anthraquinone content was 1.06 ± 0.08 - 4.82 ± 0.12 mg/g,and the total polyphenol content was 4.921 ± 0.21 - 10.02 ± 0.11 mg/g.Cluster analysis and principal component analysis showed that 20 batches of rhubarb samples could be divided into 4 class,namely Longxi County and Lintao County are the first category,Dangchang County and Li County are the first category,Min County and Zhang County are the first category,and Weiyuan County is the first category.Common peaks 7 (aloe emodin-8-O-glucoside),1,10 (emodin),2,9 (aloe emodin) had scavenging effect on DPPH free radical activity,and common peaks 7,1,10,3,8,12(emodin) and 14 (emodin methyl ether) had scavenging effect on ABTS free radical activity.This is basically consistent with the change of common peak area before and after the reaction.Correlation analysis shows that the common peaks 10 and 7 are positively correlated with the activity of scavenging DPPH free radicals,and total anthraquinones are negatively correlated with the activity of scavenging DPPH free radicals.Common peaks 2 and 11 are negatively correlated with the activity of scavenging ABTS free radicals,and total polyphenols are significantly positively correlated with the activity of scavenging ABTS free radicals.This research provides a theoretical basis for the screening of antioxidative active ingredients of rhubarb and the differentiation of rhubarb from different origins.