The invention relates to a preparation method for silicone carbide ceramics and diamond composite drawing die. The silicone carbide ceramics is taken as a substrate, and the process of conventional diamond coating deposition, plasma polishing, nano diamond coating deposition, and mechanical polishing is repeated for a plurality of times to remove original blister defects on the surface of an inner hole of a ceramic die. During the cycle of CVD diamond deposition and polishing, a conventional diamond coating is integrated with a nano diamond coating, the plasma polishing is integrated with themechanical polishing, the plasma polishing is inserted between the conventional coating and the nano coating, and consequently the die becomes more adaptive to the mechanical polishing after the growth of the nano coating. The die which can replace a traditional hard alloy product not only can greatly prolong the service life of a traditional die and device, improve production efficiency, remarkably improve the quality of products concerned and effectively save raw material, but also has great significance for the great reduction of tungsten and cobalt consumption and effective solution to the resource crisis faced by the hard alloy industry.