The invention relates to a method for preparing polytetrafluoroethylene@phenolic resin core-shell composite particles. The method for preparing the polytetrafluoroethylene@phenolic resin core-shell composite particles comprises the following steps that (1) a polytetrafluoroethylene emulsion is mixed with deionized water, and the mixture is ultrasonically dispersed to obtain polytetrafluoroethyleneaqueous emulsion; (2) a fluorine-containing surfactant is dissolved in the deionized water, and dispersion liquid of the surfactant is obtained by ultrasonic dispersion; (3) a resorcinol aqueous solution, formaldehyde and a sodium hydroxide solution are mixed uniformly in equal volume ratios to obtain a mixed solution; (4) after the polytetrafluoroethylene aqueous emulsion is mixed with the surfactant dispersion, mixed liquor is injected after mechanical stirring, and the mixture is stirred at a room temperature to 55 DEG C for 12-36 hours to obtain a red-brown solution; and (5) the red-brownsolution is subjected to freeze-drying to obtain the polytetrafluoroethylene@phenolic resin composite particles of a core-shell structure. A one-pot method is adopted to initiate polymerization on the surface of polytetrafluoroethylene particles to synthesize a phenolic resin shell layer. The core-shell morphology has a high coverage rate, and good repeatability is achieved, the method for preparing the polytetrafluoroethylene@phenolic resin core-shell composite particles can be put into industrialized large-scale production, and the application field of polytetrafluoroethylene is greatly expanded.