A method for separation and determination of 5,6,7,8-tetrahydroquinoxaline added in aromatic rice by gas chromatography-mass spectrometry was established. The anhydrous ether was extracted(Soxhlet) after drying，purified by anhydrous sodium sulfate and concentrated with nitrogen blowing，and the anhydrous ethanol was dissolved. The extract was separated by an HP-INNOWAX column and then detected by a mass spectrometer，and quantified by an external standard method. The method had a good linear relationship (R=0.9994) in the range of 5,6,7,8-tetrahydroquinoxaline concentration of 0.5~10.0 mg/L. The RSD of the method was 4.77%. The recovery rate of addition was within 81.00%~93.70%，and the detection limit (RSN=3) of the method was 0.05 mg/L. Results showed that the gas chromatography-mass spectrometry method is suitable for rapid qualitative analysis and identification of aromatic rice.