Abstract: The study aims to investigate the relationship among quality components, sensory evaluation and the optimum fermentation of congou black tea, and explore the discrimination criterion of the optimum fermentation. We conducted sensory evaluation and tested 10 quality components such as total catechin, EGC, EGCG, EC, ECG, GA, L-C, TFs, TRs, TB and so on. The inner connection of quality components of congou black tea was analyzed via dynamic clustering analysis, the test samples were classified according to the fermentation degree, then the fermentation degree results of sensory evaluation were compared, and the contribution of each quality component was determined through variance analysis. Jaccard coefficients of insufficient fermentation, optimum fermentation and over fermentation samples based on quality components and sensory evaluation were Jb=0.82, Js=0.59 and Jg=0.65, respectively. The contribution of quality components to the classification was: EC＞total catechin＞EGCG＞ECG＞L- C＞GA＞EGC＞TB＞TFs＞TRs. Quality components presented a linear change in different types. It is concluded that, according to the quality components variances of different fermentation degrees of congou black tea, it was feasible to discriminate the optimum fermentation by dynamic clustering method, and the classification results were ideal. The content change of total catechin and its components, as well as theaflavin of different fermentation degrees of congou black tea could be used as the discrimination criterion for the optimum fermentation.