The portable gas chromatography mass spectrometer (GCMS) is an analyzer based on low heat capacity chromatography combined with miniaturized quadrupole mass spec-trometry. The analyzer adopts an inert electron bombardment ion source, a miniaturized quadrupole mass analyzer, which has a fast warming thermal desorption, and low heat capacity gas chromatography. It can be stalled in a mobile monitoring vehicle or carried on the shoulder to the site for testing. It can be used for fast qualitative and quantitative analysis of volatile organic chemical pollutants (VOCs) and semi-volatile organic chemical pollutants (SVOCs) in the atmosphere, water and soil. It is also a powerful analytical tool in the fields of environmental monitoring, fire fighting and emergency response, occupational health and public safety.