The invention relates to a high-strength, high-electric-conductivity and high-stress relaxation-resistance copper alloy elastic material and a preparation method thereof, and belongs to the field of machining of nonferrous metal. The material comprises the following components in percentage by weight: 1.8-3.0% of Co, 2.3-3.6% of Ni, 1.0-1.5% of Si, 0.05-0.1% of Cr, 0.01-0.05% of Ag, 0.02-0.05% of Zr, 0.02-0.05% of B, and the balance of Cu, wherein the mass ratio of Ni/Co is 1.2-2; and the mass sum of Ag, Zr and B is 0.05-0.1%. The material is prepared through smelting, casting, uniform heat treatment, hot rolling, solid solution treatment, primary cold rolling, first-grade aging treatment, secondary cold rolling and second-grade aging treatment. The tensile strength, the electric conductivity, the ductility and the stress relaxation resistance of the material can totally satisfy the use requirements of a vehicle high-current relay and a connector.