Abstract: A method of GC-MS combined with soxhlet extraction was used for the analysis of Octamethyl cyclotetrasiloxane (D4) and Decamethyl cyclopenta siloxane (D5) in silicone gel samples. The sample was extracted with dichloromethane by soxhlet extraction,and the extracted solution was separated on a HP-5 capillary column. EI-SIM was adopted in MS. The linear relationship were found between the peak area and the mass concentration of D4 and D5 was in a certain range,with detection limits of 0.011 and 0.013 mg·L-1,respectively. The average recoveries measured by standard addition method were 90.3% and 85.1% ,and RSD were 1.5% and 1.6%,respectively.