The invention belongs to the synthesis field of organic chemistry, and relates to a preparation technology of isopropylphenazone. The preparation technology of the isopropylphenazone comprises the following steps of: adding H2 into pyrazolone for reaction under the catalytic action of a metallic reducing agent to obtain an isopropylpyrazolone reaction liquid, after hydrogenation is finished, directly pumping the isopropylpyrazolone reaction liquid into a methylation can, evaporating a solvent, after the evaporation is finished, directly adding a proportioned amount of methylation reagent into the methylation can, raising the temperature for reaction, carrying out hydrolysis reaction and basic hydrolysis reaction, lowering the temperature for crystallization, and carrying out centrifugation to obtain an isopropylphenazone crude product. According to the preparation technology provided by the invention, the isopropylpyrazolone is not subjected to centrifugation and is directly used for methylation, so that the yield loss caused by the recycling of the isopropylpyrazolone centrifugation mother liquid is reduced so as to greatly increase the yield rate of the isopropylphenazone crude product.