Abstract: To explore effective detection methods and so as to offer a new detection methods and forensic medical analysis strategies for this kind of poisoning cases a method of solid-phase microextraction (SPME)-gas chromatography-mass spectrometry (GC/MS) was established to determine clozapine concentration in samples of Chrysomya megacephala fed on different diet substrate added a certain amount of clozapine at different developmental stages including larvae and pupae. The clozapine was extracted by 100 μm polydimethylsiloxane (PDMS) fiber. Loxapine was used as internal standard and detected by GC/MS in selected ion monitoring (SIM). The analytical results showed that the detection limit of clozapine was 0.1 μg/L. The standard curve was linear in the range of 5—5 000 μg/L. The average recovery of clozapine in the range of 93%—104% in different concentration. The precisions (RSD) of inter-day and intra-day was less than 8%. This method was validated with respect to simplicity, accuracy and precision and provided a new potential effective detection strategies. It can be used for analysis of necrophagous flies samples in this kind of toxic poisoning cases.