Method for preparing celecoxib by using one-pot method

The invention discloses a method for preparing celecoxib by using a one-pot method. The method comprises the following steps: in the presence of ethidene diamine, mixing p-methylacetophenone and ethyltrifluoroacetate, and enabling the components to react completely at 40-80 DEG C without other solvent so as to obtain a reaction liquid of an intermediate DO; putting the reaction liquid into an alcohol solvent, further adding bihydrazino-benzsulfamide hydrochloride, further adding an organic acid to adjust the pH value to 3-6, controlling the temperature of a material liquid to 50-80 DEG C, andenabling the components to react completely; after the reaction is completed, adding water, cooling to 10-30 DEG C to separate out a crystal, and carrying out suction filtration so as to obtain a crude product of celecoxib; dissolving the crude product with methanol, dropping the material liquid into water, controlling the temperature of the material liquid to 40-50 DEG C in the dropping process,cooling to 10-30 DEG C to