Abstract: Esterified catechins are the major components resulting in bitterness and astringency in instant tea for the taste of additive applied products.Hence,more attention should be paid to the application of tannase in processing of instant tea for it degraded esterified catechins in tea.In this paper,the effects of tannase had been investigated on degrading esterified catechins for instant green tea solution at different concentrations,degradation values of EGCG for per unit tannase(mg)and the application of tannase in processing of instant green tea.The results showed that degradation values of EGCG for per unit tannase(mg)achieved 6.70 mg·mg-1 at diopter of instant green tea solution 2.35.The 3‰ addition of tea materials for tannase was suitable in applying to extracted and separated tea solution to obtain the instant tea powder with mellow taste.Comparing with only by extraction in hot water,applying tannase did not change the instant green tea significantly in the contents of tea polyphenols and catechins.