In this paper, the adsorption models of three SF6 decomposition gas (SO2, SOF2, SO2F2) on the Ni-doped ZnO (100) surface were established based on density functional theory (DFT). The structural and electronic properties of intrinsic and Ni-doped ZnO (100) surface after gas adsorption were analyzed to clarify the adsorption capacity and sensing mechanism. In addition, the adsorption parameters of Ni-doped ZnO (100) surface and intrinsic ZnO (100) surface were compared. The results show that Ni-doped ZnO (100) surface has a strong chemical adsorption effect on SO2 and SO2F2, while exhibits weaker physical adsorption to SOF2. Compared with intrinsic ZnO (100) surface, the adsorption capacity of three gas molecules were obviously enhanced after Ni doping, implying Ni dopant can significantly improve the sensitivity and selectivity of ZnO materials to SO2, SOF2, SO2F2 gases. Meanwhile, gas sensing experiment of intrinsic and Ni-doped ZnO materials towards SO2, SOF2, and SO2F2 was carried out. All results lay a solid foundation for exploring high-performance ZnO based sensors to detect SF6 decomposition components for GIS partial discharge defect diagnose.