The invention provides an amorphous alloy transformer and a preparation method of an amorphous alloy strip. The amorphous alloy transformer comprises an amorphous alloy core and a coil, wherein the amorphous alloy core comprises a three-phase core, a single-phase core cover and a yoke; a stereoscopic triangle core structure is adopted by the three-phase core, the three-phase core comprises three single-phase cores and the single-phase cores are seamlessly connected; each single-phase core comprises a single-phase core limb and a yoke; each single-phase core limb and the corresponding yoke are connected end to end to form a closed rectangular frame and are isosceles trapezoids; each single-phase core limb is formed by superposing amorphous alloy strip post sheets; each yoke is formed by superposing amorphous alloy strip yoke sheets; and lateral extension cords of the amorphous alloy strip post sheets and the amorphous alloy strip yoke sheets all pass through the rectangular centers of the single-phase cores. Compared with the prior art, the amorphous alloy strip prepared by the preparation method of the amorphous alloy strip has the advantages that the saturation magnetization intensity, the rectangle ratio, the coercivity, the magnetic flux and the saturation magnetostriction are improved, and meanwhile, the core loss is reduced.