本文分析９４例苯丙酮尿症患者的脑电图，结果异常率为６５％，异常表现以痫样放电为主８０％，少数为背景活动异常（２０％）。年龄越大，脑电图异常程度越重，提示早期治疗可防止或减轻脑损害。有抽搐和智力障碍表现或血苯丙氨酸浓度增高者，脑电图异常程度明显。经治疗后血苯丙氨酸浓度下降，脑电图亦明显改善。提示脑电图可以作为评价本病苯丙氨酸对脑的毒性作用的敏感指标。 EEG analysis of 94 patients with phenylketonuria was performed in this study. The abnormality rate was 65%. The abnormal manifestation was epileptiform discharge (80%) and the minority was abnormal background activity (20%). The older, the more severe the abnormal EEG, suggesting that early treatment can prevent or reduce brain damage. Have convulsions and mental retardation performance or increase blood concentration of phenylalanine, EEG abnormalities were significant. After treatment, blood phenylalanine concentration decreased, EEG also significantly improved. EEG can be used as a sensitive index to evaluate the toxic effect of phenylalanine on brain.