NOVELTY - Preparation of penoxsulam involves mixing 2-bromo-N-(5,8-dimethoxy-(1,2,4)triazolo(1,5-a)pyrimidin-2-yl)-6-(trifluoromethyl)benzene-1-sulfonamide, cuprous iodide, 8-hydroxyquinoline quinoline, potassium phosphate and difluoroethanol, completely stirring, and reacting under protection of nitrogen.    USE - Preparation of penoxsulam (claimed).    ADVANTAGE - The method environmentally-friendly provides penoxsulam, by simple process.    DETAILED DESCRIPTION - Preparation of penoxsulam involves mixing 2-bromo-N-(5,8-dimethoxy-(1,2,4)triazolo(1,5-a)pyrimidin-2-yl)-6-(trifluoromethyl)benzene-1-sulfonamide, cuprous iodide, 8-hydroxyquinoline quinoline, potassium phosphate and difluoroethanol, completely stirring, and reacting under protection of nitrogen. 2-Bromo-6-(trifluoromethyl)benzene-1,4-diamine is obtained by synthesizing 2-bromo-4-nitro-6-(trifluoromethyl)aniline as starting material, mixing with stannous chloride dihydrate and ethanol, heating, and adjusted pH value with sodium hydroxide and ethyl acetate to form alkaline solution. The 2-bromo-6-(trifluoromethyl)benzene-1,4-diamine is dissolved in dichloroethane, stirred until it is completely dissolved, acetic anhydride is added, and stirred, to obtain N-(4-amino-3-bromo-5-(trifluoromethyl)phenyl)acetamide. The obtained compound, glacial acetic acid, concentrated hydrochloric acid and sulfuric acid are mixed, and stirred with sodium nitrite, to obtain reactant solution. The reactant solution is added to solution of sulfur dioxide and glacial acetic acid, copper sulfate powder is added, and stirred until completely, to obtain 2-bromo-4-acetamido-6-(trifluoromethyl)benzene-1-sulfonyl chloride. The obtained compound is dissolved in ethanol, concentrated hydrochloric acid is added, and stirred, to obtain 2-bromo-4-acetamido-6-(trifluoromethyl)benzene-1-sulfonic acid. The obtained compound is dissolved in solution of sodium ethoxide and ethanol, and butyl nitrite is added, to reactant solution. The reactant solution is cooled, cuprous chloride and sulfuric acid are added, and heated, to obtain 2-bromo-6-(trifluoromethyl)benzene-1-sulfonic acid. The obtained compound is mixed with a solution of methanol and potassium hydroxide, stirred, and filtered, to obtain reactant solution. The reactant solution is mixed with acetonitrile, potassium salt, sulfolane and phosphorus oxychloride, heated, stirred, cooled to room temperature, poured into ice water, extracted with methylene chloride, washed with dichloromethane and water, and dried, to obtain 2-bromo-6-(trifluoromethyl)benzene-1-sulfonyl chloride. The compound is reacted with 5,8-dimethoxy-(1,2,4)triazolo(1,5-a)pyrimidin-2-amine, N-(dimethyl-4-sulfanylidene)-5,8-dimethoxy-(1,2,4)triazolo(1,5-a)pyrimidin-2-amine and acetonitrile solution, 3,5-lutidine is added, and reacted at 0-50 degrees C for 0-24 hours, to obtain 2-bromo-N-(5,8-dimethoxy-(1,2,4)triazolo(1,5-a)pyrimidin-2-yl)-6-(trifluoromethyl)benzene-1-sulfonamide.