Process for producing solvent of red 135

The invention relates to a method for preparing solvent red 135, belonging to the field of chemical engineering. Tetrachlorophthalic anhydride and 1, 8-naphthylenediamine which have the substance amount ratio being 1:1, aqueous hydrochloric acid solution with the mass concentration of 10-15%, polar organic solvent that can be mixed and dissolved with the water and non-ionic surface activity catalyst are mixed in a reaction device provided with stirring and reflow equipment, and then the mixture is stirred and heated up to a reflow state to react for 8-15h; after being filtered, filter mass is washed by clear water until the filtrate is neutral; at last, the solvent red 135 is obtained after being dried; the dosage of the aqueous hydrochloric acid solution is 10-20 times more than that of the 1, 8-naphthylenediamine, the dosage of the polar organic solvent is 1-50% of the total content of reaction medium, and the dosage of the catalyst is 0.01-2% of the total content of reaction medium. The invention has the advantages of good product quality of a solvent method and low cost of an aqueous phase method.