NOVELTY - Preparing imatinib, comprises (i) preparing beige solid, where the solid refers to N-(4-methyl-3-nitrophenyl)-4-(4-methylpiperazine-1-yl-methyl) benzamide; (ii) preparing sticky condensate of N-(3-amino-4-methylphenyl)-4-(4-methyl-piperazine-1-yl-methyl)benzamide; (iii) preparing N-(3-guanidino-4-methylphenyl)-4-(4-methylpiperazine-1-yl-methyl)benzamide; (iv) obtaining the orange solid, i.e., 1-(3-pyridyl)-3-(dimethylamino)-2-propen-1-one; (v) crystallizing the mixture, filtering and drying to obtain the beige solid, i.e., imatinib, and refining the imatinib to obtain the white solid.    USE - The method is useful for preparing imatinib.    ADVANTAGE - The method is safe, simple and economical and the reactant needs no cis-trans screening.    DETAILED DESCRIPTION - Preparing imatinib, comprises (i) adding dioxane and 4-methyl-3-nitroaniline to a reaction bottle to completely dissolve, adding anhydrous potassium carbonate, stirring the mixture at 0 degrees C and dropping 4-(chloromethyl)benzoyl chloride, dissolving the mixture in the dioxane, after dropping, stirring and reacting the mixture for 1 hour, then adding N-methylpiperazine, where the temperature during the reaction can be easily raised, stirring the mixture and maintaining the temperature until 4-methyl-3-nitroaniline completely reacts, filtrating the solid in the system, reducing the pressure of the filtrate and condensing it to dry, adding water (12 l) under violent stirring, stirring the mixture for 2 hours at room temperature, crystallizing, filtrating and drying the reactant to obtain beige solid, where the solid refers to N-(4-methyl-3-nitrophenyl)-4-(4-methylpiperazine-1-yl-methyl) benzamide; (ii) adding the prepared beige solid and ethanol to the reaction bottle, stirring the mixture and dropping hydrazine hydrate in ethanol to the system, during which a plenty of foam is generated, heating and reflowing the mixture, maintaining the reflowing state until the solid completely reacts, filtrating the catalyst, reducing the pressure of the filtrate and condensing it dry to obtain sticky condensate of N-(3-amino-4-methylphenyl)-4-(4-methyl-piperazine-1-yl-methyl)benzamide; (iii) adding the sticky condensate and isopropanol to the reaction bottle, heating and reflowing the mixture, regulating pH of the system to 1.5-2 by using concentrated hydrochloric acid to generate sticky product, then adding 50% cyanamide aqueous solution, maintaining the system to reflow for 30 hours when the pH is 3-4, displaying the condition that the reaction is ended, reducing the pressure and condensing it to dry, adding water to dissolve the condensate, then using 20% sodium hydroxide aqueous solution to regulate pH to 13 under cooling of ice water bath, during which oily matter is generated, stirring and crystallizing the reactant for more than 4 hours under ice water bath, filtrating, reducing the pressure and drying the reactant to obtain N-(3-guanidino-4-methylphenyl)-4-(4-methylpiperazine-1-yl-methyl)benzamide; (iv) dissolving N,N-dimethylformamide dimethylacetal in ethanol, raising the temperature to 60 degrees C, dropping 3-acetylpyridine to the system to prevent material clashing, reflowing the mixture for 12 hours, displaying the condition that the raw materials are completely reacted, condensing the product and removing ethanol, cooling the reactant for a little and adding mixed liquid prepared from toluene and normal hexane based on volume ratio of 3:2, stirring and crystallizing the mixture for more than 4 hours under ice water bath, filtrating the mixture to dry to obtain the orange solid, i.e., 1-(3-pyridyl)-3-(dimethylamino)-2-propen-1-one; (v) adding intermediate of N-(3-guanidino-4-methylphenyl)-4-(4-methylpiperazine-1-yl-methyl)benzamide, other intermediate of 1-(3-pyridyl)-3-(dimethylamino)-2-propen-1-one and isoamylol to the reaction bottle in the presence of nitrogen, adding the mixture to reflow, reflowing and separating the water for more than 12 hours, ending reaction and cooling, reflowing the mixture and adding ethyl acetate, stirring and crystallizing the mixture for 4 hours at room temperature, filtering and drying the mixture to obtain the beige solid, i.e., imatinib, and refining the imatinib to obtain the white solid.