Abstract: In shale oil and gas exploration, chemical tracer technology is effectively applied to the evaluation of fracturing technology. The precondition for the application of this technology is the establishment of corresponding analysis method. The authors selected 21 kinds of halogenated hydrocarbons as tracer, with stable chemistry character and low stratigraphic background values. And a high sensitivity detection method for the tracer by purge-and-trap and gas chromatography mass spectrometry (GC-MS) was developed. The conditions of purge-and-trap and GC-MS were optimized and the optimum conditions were obtained. The results showed that the detection limits were 0.027-0.162 μg/L. The average recoveries were 74.16%-121.9% with a precision lower than 12.79% (RSD, n=7). The established method is simple and fast, hence is applicable for the determination of tracer in fracturing outlet fluid samples after reservoir reconstruction.