Objective To establish a gas chromatographic method for detecting dehydroacetic acid in moon cake. Methods After samples being acidified, dehydroacetic acid was extracted with ether and detected by gas chromatography with HP-5 capillary column. Results The relative standard deviations (RSD) were 3.13%?4.73%, the recovery rates were 99.8%?85.3%, and the correlation coefficient was 0.9999. Conclusion The method is simple, rapid and accurate for the detection of dehydroacetic acid in moon cake.