The invention discloses an alloy material for a high-energy accumulator grid and a preparation method thereof. The alloy material is prepared from the chemical compositions in percentage by weight: 0.06-0.14 percent of Ca, 0.1-2.0 percent of Sn, 0.01-0.06 percent of Al, 0.01 -0.1 percent of Zn, 0.001-2.0 percent of rare earth and the balance of Pb, wherein the rare earth is one or two of Er and Yb or the mixture of Ho, Er, Tm and Yb. The preparation method comprises the following steps: adding Ca, Al and the rare earth to a crucible electric cooker according to the mixture ratio, and vacuumizing and then introducing nitrogen gas for protection at the temperature of 600-900 DEG C, and then smelting; adding Pb, Sn and Zn according to the mixture ratio, smelting at the temperature of 550-650DEG C and evenly mixing the mixture, sampling after the mixture is static (regulating alloy compositions according to the sample compositions), then fishing out dregs, keeping the temperature at the temperature of 550-650 DEG C for 0.5-3 hours, and then cooling; controlling the cooling speed at 10<2>K to10<5>K/S.