This method details the gas chromatograph mass spectrometry method for the determination of hexabromocyclododecane (HBCD) containing bromine flame retardant in Coatings. This method is suitable for the determination of hexabromocyclododecane in Coatings. In this process, the sample is first extracted by ultrasound with dichloromethane, then the extraction liquid is filtered through an organic membrane, and finally determined by gas chromatograph Mass spectrometry (GC/MS). Retention time and mass spectrometry are relied on for qualitative and quantitative analysis. In addition, the method also includes the preparation of relevant reagents and materials, as well as the list of necessary instruments and equipment.