The paper aims to measure the migration of chlorinated benzenes (chlorobenzene, p-dichlorobenzene, etc.) in thermostable food contact materials by gas chromatography-mass spectrometry. Samples obtained in migration tests in water-based, acidic, alcoholic or oil-based food simulants were extracted by certain solvents, like n-hexane or methanol. Chlorinated benzenes in the solvents were then separated by capillary column bonded with polyethylene glycol, and finally tested and analyzed by mass spectrometry. Under the optimized conditions such as extracted solvent and chromatographic column, migration of chlorobenzene, p-dichlorobenzene, etc. in food simulants can be effectively determined. The method had good linearity within the mass concentration range of 0.05-50 mg/kg (water-based simulant) or 0.2-50 mg/kg (oil-based simulant). The detection limit reached 0.02-0.1 mg/kg (water-based simulant) or 0.1 mg/kg (oil-based simulant). The recovery rate ranged from 87.6% to 113.2%. And the relative standard deviation was less than 10% (n=6). The established gas chromatography-mass spectrometry method for chlorobenzene and p-dichlorobenzene is simple, rapid and accurate. It can satisfy the requirements on inspection of chlorinated benzenes in food contact materials.