The invention provides a varistor valve plate for a lightning arrester and a preparation method thereof. The varistor valve plate is prepared by the materials comprising the following components by mole percentage: 90-98% of ZnO, 0.05-2.0% of Bi<2>O<3>, 0.05-2.0% of B<2>O<3>, 0.02-1.0% of Y<2>O<3>, 0.02-1.0% of NiO, 0.02-1.0% of Cr<2>O<3>, 0.05-3.0% of Sb<2>O<3>, 0.01-1.0% SiO<2> and 0.01-1.0% of MgO. The varistor valve plate provided by the invention has excellent integrated performance; the varistor voltage gradient reaches more than 500V/mm; the square wave discharge current capacity is greater than 400J/cm<3>; the leakage current is lower than 5.0 muA; and the nonlinear coefficient is greater than 25.0. The varistor valve plate and the method are simple in preparation technology and high in technical economy. The industrial production demand can be completely realized by the existing lightning arrester valve plate manufacturing equipment.