A method for determination of vanillin and ethyl-vanillin in milk powder was established by auto headspace solid-phase micro-extraction coupled with gas chromatography-mass spectrometry (GC—MS), and the influence factor were also studied, such as solid phase micro-extraction head, time and temperature of adsorption and desorption. As a result, the limits of determination (LOD) of vanillin and ethyl-vanillin were 0.5 mg/kg. The spiked recovery was between 90.0% and 100%, and the RSD ranged from 1.9%～4.1%(n＝6). This method could eliminate the interference of complicated matrix, conveniently, quickly and exactly, which was applicable for quick determination of vanillin and ethyl-vanillin content in milk powder.