Abstract: Based on the principles of thermodynamics and dynamics,the authors designed and developed a new device for the concentration and enrichment of hydrocarbon gases.So that it can increase the concentration of free hydrocarbons in the air by several orders of magnitude,which certainly opens up the way to further the analysis of trace hydrocarbon in petroleum geochemical exploration.It can not only improve the analysis of trace hydrocar-bon(C₁-C₇)in air samples from the surface gas bearing beds and the soil above the oil/ gas pools,but also be applied to analysing the tank-top gas and water-soluble gas as well as to petroleum chemical exploration in marine area.