Abstract: Aim:To analyze petroleum ether extracts of Xiaoxuming decoction and develop the methods for the quality control of the extract.Method:A method based on GC was developed.In qualitative analysis,samples were analyzed before and after derivation.In quantitative analysis,MS and FID detectors were used.Result:Cinnamic aldehyde was detected without derivation.And three kinds of fatty acids existing in almond oil were detected after derivation.Under the selected condition,cinnamic aldehyde was separated and detected.MS and FID detection generated the recoveries of 104.2% and 103.8% of cinnamic aldehyde with RSDs of 2.2% and 2.8%,respectively.Conclusion:This method is simple and reproducible,and it can be used for the quality control of petroleum ether extracts of Xiaoxuming decoction.