Abstract:A method was developed for rapid determination of fumigant methyl bromide in foods by ion mobility spectrometry.The condition of the sample pretreatment and the detection instrument were optimized：headspace mode；the extraction solvent was saturated sodium chloride solution；ion mobility spectrometry was carried innegative ion mode；high pure air was used as carrier gas；the inlet temperature was set at 60 ℃；the detector temperature was set at 45℃；the column temperature was set at 40℃；drifting gas flow was 250 mL/min；carrier gas flow was 2 mL/min.The detection limit of methyl bromide（LOQ）was 0.05 mg/kg；the relative standard deviation of RSD<8.0%（n=10）；the Individual samples analysis period was less than 10 min.