Due to the extreme high global warming potential and long atmospheric lifetime of SF_6,the removal of SF_6 using dielectric barrier discharge (DBD) plasma technology has been a hot and difficult problem in the field of environmental protection. When the DBD reactor is placed in different ambient conditions,the discharge characteristics of DBD and the temperature rise of the reactor will show differences due to the incomplete contact between the electrode and barrier dielectrics as well as the different properties of different ambient media. The discharge characteristics and temperature changes were both measured when the DBD reactor was exposed in the air and immersed in the oil. The effects of ambient medium on the removal of SF_6 were investigated by comparing the removal rate of SF_6,energy yield and the final degradation products in both two ambient conditions. The experimental results show that the discharge power of the reactor immersed in oil is significantly higher than that in the air environment although its temperature is relatively lower. Therefore,more energy is used for the abatement of SF_6 in oil ambience,which improves the removal rate. In addition,a greater energy yield is also achieved in oil ambience. This suggests that the immersion of the plasma reactor in electrically insulating oil enhances the performance of SF_6 removal.