The invention discloses a rubber used for a generator shock pad. The rubber comprises the following raw materials: natural rubber, DBD, zinc oxide with 100 meshes, stearic acid, CTP, spray carbon black, DCP, BMI, TMTD and CZ, m-phenylenediamine, and bisphenol A epoxy resin. A preparation method comprises the steps of premixing, mixing and sulfuration. The rubber compound can be fully activated through mixing, so that heat resistance, aging resistance and anti-deformation capability of the rubber compound can be enhanced, m-phenylenediamine and BMI are premixed before a sulfuration step, so that toughness of BMI can be enhanced, an additive reaction of bisphenol A epoxy resin and m-phenylenediamine is carried out, m-phenylenediamine, bisphenol A epoxy resin and BMI are compatible, anti-shearing intensity and age-proof performance of the rubber are enhanced, CZ and TMTD are added for increasing sulfuration speed and scorching-resistant performance, and the finally obtained rubber has advantages of good breaking strength, fracture elongation and appropriate hardness, excellent high temperature resistance and good damping effect.