The invention discloses a solvent-resistant inert resin coated fluororubber sealing rubber plug and a manufacturing method thereof. The sealing rubber plug comprises the following raw materials: fluororubber, a reinforcing agent, a filling agent, a processing aid, an acid acceptor and a cross-linking agent system, wherein the sealing rubber plug further comprises a fluorine resin film which coversthe neck part of the sealing rubber plug and is subjected to corona discharge treatment; the thickness of the fluorine resin film is 5-100 [mu]m, and the fluorine resin film is one of an ethylene-tetrafluoroethylene copolymer film, a tetrafluoroethylene-perfluoropropyl perfluorovinyl ether copolymer film, a chlorotrifluoroethylene polymer film and a polyvinylidene fluoride film. The preparation method comprises the following steps: rubber material mixing, primary sheet discharging, fluorine film slicing, primary laminating vulcanization, primary punching, secondary sheet discharging, secondary vulcanization and secondary punching. The surface, in contact with a solvent, of the sealing rubber plug is coated with a layer of an inert film, low-molecular-weight organic matters in rubber can be prevented from migrating to the solvent end, the influence of dissolved matters on an organic solvent is avoided, and inaccuracy of a detection result is avoided.