Abstract: Eliminated laying hee was used as the ingredients of herbal chicken soup,and the soup was concentrated in two different ways:atmospheric evaporation and vacuum evaporation which then compared and analyzed the volatile flavor compounds by the means of gas chromatography-mass spectrometry. The result showed that 29 kinds of compound were detected in the process of atmospheric concentration,while 45 kinds of compound were detected in the process of vacuum concentration. Also,aldehydes was reduced by 24.87% in the process of Vacuum concentration and the hydrocarbons and esters was increased by 18.58% and 9.81%,From fat oxidation product hexanal was significantly redued by 10.67%( p <0.05), heptanal octyl aldehyde were reduced by 1.24%,1.62%,and pentyl furan from the Maillard reaction product reduced 4.04%(p<0.05).The results showed that the vacuum concentration process to retain the unique Diet chicken flavor compound content and reduce aldehydes,which had a significant effect on concentrated medicated chicken volatile compounds.