The solidification experiment of Cu-25%Ag alloy used in high field magnet was carried out under HMF (high magnetic field), then the ingots were cold drawn into wires. The solidified structure, drawn structure and electrical conductivity were investigated systematically. In the case of no HMF, it is found that the columnar Cu dendrites is longer, moreover, on top of the sample the dendrites grow along the radial direction of the arc; on the middle part, the angle between the dendrites growing direction and axis of the ingot is about 45°; on the bottom part, the angle is about 90°. In other sides, the thickness of eutectic is thinner, the two phases present a non-uniformity distribution and the lamellar spacing is larger. In the case of HMF, the cellular Cu dendrites is shorter, moreover, on top of the sample the dendrites grow along the radial direction of the arc; on the middle and bottom parts the angle between the dendrites growing direction and axis of the ingot is about 90°, the thickness of eutectic is thicker, the two phases present a uniformity distribution, and the lamellar spacing is smaller. After cold drawn treatment, the eutectic “net” structure changes into filamentary structure. The thickness and spacing of the eutectic filamentary are thinner in the case of no HMF, but the thickness and spacing of the eutectic filamentary are thicker with in the case of HMF. By the influence of the filamentary structure, the electrical conductivity of the wires is different with and without HMF