The invention relates to an azasetron hydrochloride compound comprising the following processing steps and a preparation method thereof. The preparation method comprises the following steps: (1), adding an azasetron hydrochloride insoluble solvent to azasetron hydrochloride as a raw material, controlling a temperature to be not more than 30 DEG C, tempestuously agitating the mixture, and then, filtering the mixture, washing a filter cake by using the azasetron hydrochloride insoluble solvent with the temperature not more than 20 DEG C, and drying the filter cake in a vacuum way or airing the filter cake in air; (2), putting the filter cake in ammonia water, agitating the mixture tenderly, controlling a pH value to be not more than 9 to obtain the ammonia water solution of the azasetron hydrochloride, and then, filtering out a precipitate which is separated out; (3), adding ethyl alcohol with a concentration of 75% in the ammonia water solution of the azasetron hydrochloride until absolute ethyl alcohol is obtained, and then, dripping a concentrated hydrochloric acid, controlling the temperature at 30-60 DEG C, controlling the pH to be 0.5-3.0 finally, keeping the mixture for 30 minutes to 5 hours, slowly separating out a crystal, and then, gradually decreasing the temperature to a lowest temperature of 10 DEG C, standing to crystallize, sucking a filtrate, and drying the crystal in the vacuum way to obtain an azasetron hydrochloride competitive product; and (4), optionally returning a crystallizing mother solution after the crystal is separated out to the step (3). By using the method provided by the invention, the purity of the azasetron hydrochloride is improved greatly; the contents of relevant substances are decreased obviously; the quality of a preparation productis improved; and toxic side effects are reduced.