Gas chromatography was used to analyze the petroleum hydrocarbon degradation products of a highly efficient petroleum hydrocarbon degrading strain Stenotrophomonas acidaminiphila. More than 80% of petroleum hydrocarbons were degraded.UCM peak appeared in the product chromatogram.The results indicated that the strain was able to degrade most of the C10-C28 n-alkanes,some straight-chain alkanes and cycloalkanes, while the aromatic hydrocarbons,especially polycyclic aromatic hydrocarbons,were difficult to degrade by the strain According to the intermediate products detected,straight-chain alkanes,such as hexadecane,under the action of microorganisms,generate intermediate products hexadecanol,which was then oxidized to hexadecaldehyde and fatty acids.Fatty acids are further oxidized to finally produce CO, and H,O.The degradation pathway of branched-chain alkanes is similar to that of straight-chain alkanes,and the intermediate products detected were2-hexyl-1-dodecyl alcohol,2-octyl-1-decan