Green tea extracts were used to investigate the improvement of color and the changes of physiological ac-tivities for the better application to food, cosmetics or pharmaceuticals by removing undesirable color. Hunter color L-value of the green tea extract was increased and a- and b-value were decreased by irradiation re-gardless of doses, resulting in a bright yellow-colored green tea extract from dark brown. Both inhibition effect of tyrosinase and electron donating ability were not changed by irradiation treatment (P>0.05). Irradiation tech-nology can be applied to various functional products to improve color without changing physiological activities.