Abstract: In order to explore the effect of fluorination temperature on the flashover performance of epoxy insulators, epoxy samples were fluorinated in a laboratory stainless vessel using a F₂/N₂ mixture with 12.5% F₂ by volume at 25 ℃, 55 ℃ or 85 ℃ for 30 min. Then characterized their physicochemical characteristics and conducted electrical performance test. DC flashover tests indicate that direct fluorination significantly increased the DC flashover voltage of epoxy insulators in SF₆ gas, and the DC flashover voltage increased with the increase in fluorination temperature. Attenuated total reflection infrared analysis and scanning electron microscopy observation indicate that direct fluorination changed the surface chemistry of the epoxy sample, forming a fluorinated layer that thickens with fluorination temperature and has a micro rough surface. Measurements of surface potential decay and surface conductivity indicate that direct fluorination enhances surface electrical conduction of epoxy insulators, and surface conductivity increases with the increase of fluorination temperature. The improvement of DC flashover performance of epoxy insulators is mainly attributed to the suppression of surface charge accumulation by the enhanced surface conduction.