Abstract: A gas chromatography-mass spectrometric method for determination of deca brominated diphenyl ether (BDE 209) was developed by optimizing the instrumental operating conditions. In addition, a sample preparation method for determination of BDE 209 in soils by accelerated solvent extraction(ASE) was investigated based on the strict QA/QC protocols. The detection limits of the instrumental and the method were 9.75 pg and 3.25 ng/g respectively. The mean recovery was 86.8％ with precision of 5.56%RSD. The surrogate standards were used in comparison of extraction efficiency for ASE, microwave extraction, ultrasonic extraction and Soxhlet extraction techniques and the results showed that the similar recovery of 97.7%～108% was obtained, which means that all the extraction methods mentioned above are suitable for determination of BDE 209 in soil samples.