The utility model discloses a tri -axial linkage device for spark -erosion machining, including base, stand, X axis platform, Y axis platform, Z axle processing agency and work rest, surface parallelis provided with a plurality of X axle guide rails and one set of X axial filament pole that is equipped with the X spindle nut on the base, the X axis platform lower surface is provided with the X axle slider of a plurality of confession X axle guide rail embedding, fixed surface is connected under X spindle nut and the X axis platform, Z axle processing agency erects roof beam, Z axle motor, Z axial filament pole and electrode grinding head by the Z axle and constitutes, side surface that the Z axle erected the roof beam through a mounting panel with stand swing joint, Z axle motor is fixedin the Z axle and erects on the roof beam, Z axial filament pole is fixed in the output of Z axle motor, be fixed with the spindle nut with Z axial filament pole complex Z on the mounting panel, driveZ axle processing agency along Z axle motion, electrode grinding head installs and erects roof beam lower extreme surface in the Z axle. The utility model discloses the mechanical structure who utilizes tri -axial linkage combines together with spark -erosion machining, can reduce the cost of processing to can realize the effective processing to large tracts of land polycrystalline diamond.