The invention discloses a preparation method of a high-hardness hardfacing electrode, and belongs to the technical field of surfacing electrode preparation. The preparation method comprises the steps that calcined matter obtained through pulverized fuel ash calcination is smashed and screened; after the calcined matter, graphite, vanadium chloride and absolute ethyl alcohol are prepared into slurry, the slurry, a nickel nitrate solution and calcium oxide are mixed for a high-pressure reaction; filtered-out filter residues are washed with distilled water and calcined, and an electrode matrix is prepared; then the electrode matrix, marble, white mica and high carbon ferromanganese are ground and screened, screened particles are collected and stirred with a sodium silicate solution, and sintering is carried out after air drying; then baked matter is smashed and screened to prepare powder; finally a core wire is placed in an electrode coating machine, the powder is evenly extruded on the periphery of the core wire, and an electrode is prepared; and the electrode is placed in a sintering furnace for sintering and baking treatment, the electrode is taken out through furnace cooling, and the high-hardness hardfacing electrode can be obtained. The preparation method is easy and convenient to operate; the obtained electrode is good in forming and high in hardness; the phenomena of cracking and the like are not prone to happening during use; and wide application prospects are achieved.