To investigate the evaluation method and standard of the quantity rating of Huanglian medicinal materials related to the external traits and intrinsic quality.Methods:To construct a method for evaluating the quality grades of Rhizoma Coptidis based on correlation between appearance traits and intrinsic quality by using 18 batches of commercially available Rhizoma Coptidis.Eighteen batches of Rhizoma Coptidis were tested for moisture,ash,extractum,length,diameter,berberine content,epiberberine content,coptisine content,palmatine content and chromaticity.Mathematical and statistical tools such as principal component analysis(PCA),correlation analysis and analysis of variance were used to screen the grading indexes.Results:Length,extractum and berberine content were considered as the key indexes for the quality evaluation of Rhizoma Coptidis,and the extrinsic index(length) and intrinsic quality indexes(extractum and berberine content) were positively correlated at 0.01 significance level.Finally,the standards of first grade,second grade and general grade quality of Rhizoma Coptidis were developed in combination with the actual market situation.Conclusion:The quality grades not only evaluated Rhizoma Coptidis in terms of appearance characteristics,but also characterized it in terms of intrinsic quality differences,which made up deficiencies for the existing group standards and also provided the basis for establishing subsequent industry standards or national standards.