The invention discloses a high-power alloy foil resistor which comprises a substrate, a resistor element attached to the substrate and electrodes connected to the two ends of the resistor element. The resistor element comprises an intermediate material piece and two resistor alloy pieces, the middle material piece is clamped between the two resistance alloy pieces and is connected with the two resistance alloy pieces at the same time, the two resistance alloy pieces are connected with the electrodes at the two ends respectively, and the intermediate material piece is made of a low-resistivity high-thermal-conductivity metal material. As the middle area of the resistance element is replaced by the low-resistivity high-thermal-conductivity material, a heat accumulation area is divided into two parts. The heat accumulation points of the resistor element can be segmented, and a heat transmission path is shortened, so that the heat dissipation capability of the whole resistor is improved, and the service power of a product is improved. Meanwhile, the middle part of the resistor element is replaced by the low-resistivity metal, so that the designed length of the resistor element is reduced, and the resistor with a lower resistance value can be designed and produced.