A method was established to direct determination of organic selenium in food. The organic selenium was extracted by adding cyclohexane in aqueous solution with pH value of 7.0, and the content of organic selenium was determined by inductively coupled plasma mass spectrometry after microwave digestion. In the best test conditions, the limit of detection and quantification were 0.45 μg/kg and 1.5 μg/kg, respectively. The recoveries ranged from 93.5% to 103.0%. The method has many advantages such as simple operation, high precision, wide linear range and so on, and can be used for accurate determination of selenium in food. So it has a wide application prospect in practical detection.