Abstract: A method of LC-MS was applied for the determination of hexabromocyclododecane in soils and sediments. The sample was extracted with a mixture of n-hexane and dichloromethane using. Soxhlet extractor or ASE Accelerated Solvent Extractor,and then purified on silica gel column. The Hypersil C18 column was used as stationary phase and the mixture of water and methnol-acetonitrile was used as mobile phase for gradient elution. ESI- and SRM were adopted in MS/MS detection. The linearity ranges for α-hexabromocyclododecan β-hexabromocyclododecane and γ-hexabromocyclododecane were all within 5.0-500 μg·L-1,with detection limits(3S/N) of 12.5,12.4 and 9.95 ng·kg-1,respectively. The method was used to measure soils and sediments samples,recovery rate measured by standard addition method was in the range of 78.5%-111% with RSD′s (n=7) in the range of 4.1%-11%.