In order to solve the limitation of intrinsic carbon nanotubes in SF6 gas sensing detection,a method was proposedto study the gas-sensitive properties of SF6 discharge decomposition based on modified carbon nanomaterials.The air plasma was used to modify the intrinsic carbon nanotubes and pretreat the surface of carbon nanotubes,and the gas sensing response characteristics of the modified carbon nanotubes in detecting the decomposition components of SF6 was investigated.The results show that the air plasma-modified carbon nanotube gas sensor is more sensitive to the resistance change of H2S gas than the intrinsic carbon nanotube,and has a shorter response time,good repeatability and stability.The air plasma modified carbon nanotube gas sensor is much less sensitive to the change in resistance of SO2 gas.Carbon nanotube gas sensors with different dopant ratios have different sensitivity responses to SOF2 and SO2F2 respectively.Therefore,the intrinsic carbon nanotube gas sensor modified by air plasma can accurately reflect the discharge decomposition of SF6 gas and provide a basis for the detection of SF6 gas composition.