Tert-butylhydroquinone(TBHQ)in oil was detected by liquid chromatography-electrochemical reduction device.The sample was mixed with acetonitrile,extracted by ultrasound, filtrated by centrifuge and determined.The results showed good linearity for TBHQ with the concentration in the range of 0.50～30.00 mg/L,the correlation coefficient 0.998 7,the minimum detection limit 0.05 mg/L,RSD 1.78%,the recovery 90.32%～93.40%.To affect the result caused by TBHQ being oxidized during storage was avoided by electrochemical reduction.This method is simple in sample pretreatment,has good stability,accuracy and reliability.