The invention discloses a preparation method capable of remarkably overcoming the surface defect of a copper alloy material for a lead frame. The preparation method comprises the following steps that S1, a copper-iron alloy with the iron content being 7% is refined; S2, high-purity copper and wood coal are added into a high-frequency induction smelting furnace, heating is conducted until the high-purity copper is completely melted to obtain copper liquid, heating continues to be conducted, the copper-iron alloy with the iron content being 7%, a copper-zinc alloy, a copper-phosphorus alloy, a copper-tin alloy, a copper-titanium alloy and mixture rare earths are added, and stirring and smelting are conducted to obtain a copper-alloy solution; S3, the components of the copper-alloy solution are detected, and casting is conducted to obtain strips; S4, the strips are subjected to uniform annealing, the annealing temperature is 650-730 DEG C, repeated hot rolling is conducted, then the strips are transferred to be subjected to intermediate annealing finish rolling, the intermediate annealing temperature is 690-710 DEG C, and then a finish rolling product is obtained; and S5, the finish rolling product is subjected to ageing treatment and cooled with a furnace to obtain the copper alloy material, with the surface defect remarkably overcome, for the lead frame. According to the preparation method capable of remarkably overcoming the surface defect of the copper alloy material for the lead frame, uniformization of the copper alloy material for the lead frame is promoted, the surface performance of the alloy material is improved, and the comprehensive performance of the copper alloy material is improved.