O-benzoquinones， generated by the oxidation of polyphenols， are highly electrophilic compounds and may react with many kinds of nucleophiles in food systems， and therefore cause nutrient losses and food safety problems. The interaction of quercetin quinone with five kinds of amines， two kinds of thiols and bovine serum albumin （BSA） were investigated at pH 5.0， 7.0 and 8.0 by electrochemical workstation. Quercetin quinone reacted with selected nucleophiles more efficiently at pH 7.0 and 8.0 than that at pH 5.0. In addition， reaction of quercetin quinone with thiols was found to be faster than that with amines. At pH 7.0 and scan rate of 10 mV/s， amines（16.0 mmol/L） reaction with quercetin quinone （0.08 mmol/L） followed the order： L-lysine （55.13% ± 5.37%） > L-arginine （39.58% ± 4.64%） > L-methionine （17.80% ± 2.72%） > glycine （~0.00%）≈Nα-acetyl-L-lysine （~0.00%）. Thiols （0.048 mmol/L） reaction with quercetin quinone （0.08 mmol/L） under the same conditions followed the order： L-cysteine （63.17% ± 1.51%） > Nα-acetyl-L-cysteine（54.28% ± 2.60%）>BSA （37.55% ± 5.98%）. These data proved that O-benzoquinone formed by the oxidation of quercetin could modified proteins and eliminated essential amino-acids.