The invention discloses a common-mode radiation resistant cable material for computers and a preparation method thereof, and relates to the technical field of computer cables. The cable material comprises the following raw materials: chlorinated polyethylene rubber, PBT resin, an acrylonitrile-butadiene-styrene copolymer, ZAO slurry, iron oxide powder, modified graphene, chlorinated paraffin, silicone master batch, ferrocene, trioctyl trimellitate, hindered phenol, t-butyl aryl phosphate, an aluminium-zirconium bimetallic coupling agent, a cross-linking agent, a promoter and an anti-aging agent. The preparation method comprises steps of mixing of the raw materials, extruding and granulation and the like. The cable material is convenient to prepare, is low-cost, is green and environmentally-friendly, has excellent functions of common-mode radiation resistance and resistance to electromagnetic interference, has stable and excellent physical and chemical properties, has long service life,and is safe and reliable.