Yellow light was used to irradiate plucked leaves during its withering.The withered leaves were subjected to cutting and drying.The qualities of black tea were analyzed.The results showed that yellow light significantly improved the aroma and taste.The sweet flavor and fresh and mellow taste of black tea was less affected.The concentrates of catchins,theaflavins,amino acids and aroma components except polyphenols and soluble sugars were significantly increased as well.After irradiation of yellow light,the total content of catechins in black tea increased by 21.6%,among which EGCG,ECG,GC and EC were increased remarkably with no significant difference in EGC and C.The total content of theaflavins in black tea withered with yellow light had an increase of 17.6%.But each theaflavin showed different variation with a significant increment in TF1 and TF2A,but there was no significant difference in TF3 and TF2B.It is indicated that the amimo acids of black tea withered with yellow light increased by 6.8% with a significant increment in aspartic acid,glutamic acid,yaline,isoleucine and theanine.The result of GC/MS analysis showed that there was 21.7% increase of total content of aroma components.The predominant types of acids and anhydrides,alcohols,esters and aromatic compounds increased by 58.5%,41.2%,25.4% and 18.6%,respectively.Amides decreased by 127.3%.It is indicated that yellow light irradiation during tea leaves withering can improve the qualities of black tea.