The invention discloses a magnetic powdered resin with high specific surface area and a preparation method and application thereof, and belongs to the field of resin materials. The average particle size of the magnetic powdered resin is 1 to 60mum, the specific saturation magnetization degree is 0.1 to 20emu/g, and the specific surface area is 800 to 1,600m<2>/g. The resin is prepared by adopting a membrane emulsification-suspension polymerization method, divinyl benzene is used as a reaction monomer, magnetic particles are modified by oleic acid and then subjected to membrane filtering emulsification together with the oil phase, emulsion is suspended and polymerized to form the magnetic microsphere resin, and the specific surface area of microspheres is further enlarged by post cross-linking reaction. Magnetic nano particles in the magnetic microsphere resin prepared by the method are distributed uniformly and have excellent separation performance; the particle size of the resin is small and uniform, so the resin has good adsorption dynamics performance and can realize quick enrichment; and due to the high specific surface area and a rich pore structure, the resin has large adsorption capacity for various polar and non-polar organic substances.