Abstract: A tube made of oxygen free copper is filled with a plurality of copper matrix Nb—Ti superconducting lead wires to obtain a composite billet. The resulting billet is subjected to hydrostatic pressure extrusion. Further, ageing heat treatment and wire drawing process are repeated for the composite material three times to prepare a Cu/Nb—Ti superconducting single wire. Then, the resulting Cu/Nb—Ti superconducting single wires are stranded each other to produce a superconducting strand. The superconducting strand is coated with an aluminum alloy to which either a content of 20 to 100 ppm of Cu and Mg or Mg, or a content of 10 to 120 ppm of Si and Cu is added by means of hot extrusion, the strand thus extruded is reduced by 0 to 20% in accordance with cold working to produce an aluminum stabilized superconductor.