To establish a method of gas chromatography-mass spectrometry with microwave digestion and solid phase extraction to determine bisphenol A in styrofoam fast food boxes. Methods 0.2 g styrofoam fast food boxes was digested in microwave tank, then cleaned by the cartridge (C₁₈, 500 mg,6 ml) and derivated by 100 μl BSTFA-TMCS (99∶1, V/V). Finally, 1 μl solution was injected into GC-MS instrument. Results The linearity range was 0.305 to 3.05 mg/L, r²=0.991. The average recoveries ranged from 90% to 101%, and the coefficient of variation varied between 2.6% to 5.0%. Detection limit for bisphenol A was 15 μg/kg in 0.2 gram sample. Conclusion The method could be used in determination of bisphenol A in styrofoam fast food boxes for its good precision of qualification and quantification.