The invention discloses continuously cast high-strength high-conductivity copper alloy and a preparation method thereof, and belongs to the field of copper-based electrical engineering alloy. The high-strength high-conductivity copper alloy is prepared from, by weight, 0.05-3.0 parts of Zr, 0.05-3.0 parts of Mo, 0.05-3.0 parts of Yb, 0.05-3.0 parts of Gd, 0.05-3.0 parts of Er and the balance Cu. The high-strength high-conductivity copper alloy prepared through the continuous casting method is uniform in chemical component, continuous feeding, melting and continuous casting can be achieved, large-scale production is achieved, the oxygen content of bar billets is smaller than or equal to 20 ppm, and the defects of oxidization, impurities, loosening, shrinkage and the like are avoided. The alloy machining technology is simple, the yield is high, performance consistency is good, and the alloy has the characteristics of being good in conductivity and heat conductivity, high in room temperature intensity, resistant to abrasion, high in softening temperature and conductivity rate and the like and can be used as conductive rods, resistance welding electrodes, lead frameworks, overhead conductors, commutator segments and other materials in the power industry, the energy industry, the electrical engineering industry, the electronics industry, the electromechanicss industry, the traffic industry and other industries.