The invention discloses a preparation method of a copper-tantalum composite wire with high strength and high conductivity. The method comprises the steps of (1) overlapping a pure tantalum foil and ananaerobic copper foil, jointly winding on a central copper rod, and forming a densely arranged winding copper foil-tantalum foil composite; (2) loading the copper foil-tantalum foil composite into acopper sleeve body, vacuum seal welding, and carrying out isostatic cool pressing treatment and hot extrusion processing, so as to obtain an extrusion composite rod; (3) drawing to obtain a compositecore rod; (4) after sizing and cutting, straightening and acid pickling, loading a multi-core bundle into a copper pipe, carrying out hot extrusion and drawing processing, and cooperating with intermediate annealing, so as to obtain the copper-tantalum composite wire with high strength and high conductivity. According to the preparation method of the copper-tantalum composite wire with high strength and high conductivity provided by the invention, the copper foil and the tantalum foil are selected as raw materials, so that the plastic deformation degree of tantalum is greatly reduced, a Cu / Tainterface is remarkably increased, the advantages of the high shear modulus and the high strength of the tantalum are fully played, the mechanical property of the wire is further improved, and the copper-tantalum composite wire with high strength and high conductivity can be applicable to a high field pulse magnet.