Partial discharge (PD) in gas insulated switchgear (GIS) is one of important factors causing accidents. The PD can lead to the decomposition of SF6, generating different gas components. To detect and analyze the decomposed characteristic components of SF6 under PD is significant for fault diagnosis of GIS. However, how to detect the characteristic components from mixed gas components is a main puzzler. In this paper, the molecular dynamics simulation software of MS is used to calculate accurately the process of single-wall carbon nannobutes modified by hydroxide radical (SWNT-OH) adsorbing the main components of SF6 decomposed under PD. The main components contain SOF2, SO2F2, SO2 and CF4. By analyzing the frontier orbital of gas molecules and SWNT-OH, as well as adsorption energy, charge transfer and the electronic density of states in the adsorption process, and the values of energy gap after SWNT-OH adsorbing the gas molecules, the sensitivity and the selectivity of SWNT-OH on gas molecules are evaluated and the theoretical basis on whether the SWNTOH can be prepared as gas sensors to detect the components of SF6 decomposed under PD is presented.