The invention relates to a polyethylene ion permeable membrane and a preparation method thereof, comprising the following materials by weight part: 30-35 parts of silicon dioxide, 10-15 parts of polyethylene, 1-1.5 parts of color batch, 50-55 parts of stuffing bulking agents, and 0.1-0.2 part of antioxidant; the materials are uniformly mixed in a material mixing system, the mixed material is fed to a double screw extrusion machine uniformly through a discharging machine, and the material is discharged after being pressurized and melted by the double screw extrusion machine; the discharged mixture is formed by a forming machine, the formed semi-finished polyethylene ion permeable membrane is arranged in an oil extractor which is filled with trichloroethylene, so as to carry out oil control to the permeable membrane; the permeable membrane after oil control is carried out is dried, surface-activated, rolled and post-processed for obtaining finished products. The method has the advantages of low electric resistance, small bore diameter, high aperture ratio, uniform pore distribution; the permeable membrane has strong anti-piercing performance, corrosion resisting performance and oxidation resistance, and the whole production process is clean without pollution.