To establish a standard gas chromatographic method for determinating acephate in air of workplace.Acephate in the air was collected with polyurethane foamed plastics, desorbed with methanol, separated and determined by capillary GC column.The penetrant capacity of polyurethane foamed plastics tube was more than 2.4 mg, the desorption efficiency was above 90%, the recoveries of diazepam were 95.4% - 100.5%, the relative standard deviation varied from 5.1% - 7.4%, the detection limit was 0.31 microg/ml.The method is suitable for the determination of acephate in the air of workplace.