Short chain fatty acids (SCFAs) are important metabolites of gut microbiota,and are currently important media and approaches for studying gut microbiota,diagnosing and treating intestinal diseases and metabolic diseases. Feces are closely related to the intestine,and the types and abundance of fecal SCFAs can sensitively reflect the changes in the intestinal microenvironment and gut microbiota. It is currently one of the most widely studied biological samples for SCFAs. However,SCFAs are highly polar,volatile,low in content and complex biological matrix,which makes the accurate quantification of SCFAs have great troubles and challenges. Therefore,the establishment of a detection method with simple operation,high sensitivity and low cost of analysis is of great significance for analyzing SCFAs in feces. In order to be more suitable for the trace detection of SCFAs in biological samples,propyl chloroformate was used as the derivatization reagent,combined with head spacesolid phase microextraction (HSSPME) technology for the analysis of SCFAs in rat feces. The conditions were optimized. The derivatization conditions were pH8.0,300 μL propanol,100 μL pyridine,100 μL propyl chloroformate and vortex derivatization for 2 min. The conditions of HSSPME were pH 3.46,extraction temperature 50℃,extraction time 40 min and stirring speed 1 000 r/min. Under optimized conditions,a derivatization HSSPMEGC method for analyzing free SCFAs in rat feces was established. The LOD and LOQ of the method established were between 0.1330.420 μmol/kg and 0.4441.400 μmol/kg,far lower than the LOD and LOQ of the method in the literature. The linear relationship was good (R2>0.99). The accuracy was high,the recovery rate of standard addition was between 65.42% and 117.69%,and the RSD was lower than 11.60%. The method is simple,fast,sensitive and low in cost,and can fully meet the needs for trace detection of shortchain fatty acids in feces. It will provide new technical support and reference for trace analysis of SCFAs in complex biological samples including blood and tissue as well.