Syntheses of two very important derivatives of quercetin,troxerutin and 3’,4’,7-triacetoxyethoxyquercetin were described.The latter was synthesized by highly selective esterification reaction in first time.The compounds were characterized by NMR,IR and Mass spectroscopy.Additionally,the antioxidant activities of the compounds were tested by means of improved pyrogallol autoxidation method.This was the first in using this method to test the antioxidant activities of these two compounds in vitro.The optimum system of pyorgallol autoxidation spectrophotometry was investigated and established according to the reaction rules.The assay indicated that these compounds showed noticeable antioxidant activities,and compound 2 was much more effective as a free radical scavenger than the compound 1 vitamin C was used as a reference material. Syntheses of two very important derivatives of quercetin, troxerutin and 3 ’, 4’, 7-triacetoxyethoxyquercetin were described.The latter was synthesized by highly selective esterification reaction in first time. The presentations were classified by NMR, IR and Mass spectroscopy. Additionally, the antioxidant activities of the compounds were tested by means of improved pyrogallol autoxidation method. this was the first in using this method to test the antioxidant activities of these two compounds in vitro. optimum system of pyorgallol autoxidation spectrophotometry was investigated and established according to the reaction rules. These assays showed that these compounds gave noticeable antioxidant activities, and compound 2 was much more effective as a free radical scavenger than the compound 1 vitamin C was used as a reference material.