The invention relates to a technology for producing 5-acetyl amido benzimidazolone. The condensation process is as follows: o-phenylendiamine, carbamide, water and concentrated sulfuric acid are added into a condensation reaction kettle step by step, the pH value is controlled to between 6 and 7, and benzimidazolone is obtained by drying the mixture; the nitration process is as follows: the benzimidazolone, chlorinated benzene and concentrated sulfuric acid are added into a nitration reaction kettle, the chlorinated benzene is reclaimed and purified by reduced pressure distillation and water boiling, and 5-nitryl benzimidazolone is obtained by drying the mixture; the reduction process is as follows: the 5-nitryl benzimidazolone, iron powder, hydrochloric acid and water are added into a reduction reaction kettle, the mixture is subject to suction filtering, cooling, crystallization and drying after the reaction for producing the 5-amino benzimidazolone; and the acetylization process is as follows: the 5- amino benzimidazolone, Diketene, phosphoric acid, caustic soda liquid and water are added into an acetylization kettle, the pressure inside the kettle is discharged in the temperature rising process, and the mixture is subject to suction filtering and drying to produce the 5-acetyl amido benzimidazolone. The process has the total yield coefficient up to 75 percent, purity quotient more than 99 percent and the product quality which meets the international standards of the same products at home and abroad.