NOVELTY - 4-Decyloxy-3-ethoxyaniline hydrochloride, potassium carbonate, ethoxy methylene ethylene dioxy diethyl maleate, and absolute ethyl alcohol are added and stirred, filtered, concentrated and recrystallized to obtain 2-((4-n-decyloxy-3-ethoxy amino biphenyl)methylene) malonate. The obtained compound and diphenyl ether are added, reacted under protection of nitrogen at 250 degrees C for 4-6 hours, cooled to room temperature, the solution is poured into petroleum ether, precipitate is separated, and recrystallized to obtain 6-n-decyloxy-7-ethoxy-4-hydroxyquinoline-3-ethyl acetate.    USE - Manufacture of 6-n-decyloxy-7-ethoxy-4-hydroxyquinoline-3-ethyl acetate used as drug for treating coccidial infection (claimed). The drug is preferably used as veterinary medicine.    ADVANTAGE - 6-n-Decyloxy-7-ethoxy-4-hydroxyquinoline-3-ethyl acetate is manufactured with high selectivity and yield, without affecting environment.    DETAILED DESCRIPTION - Hydrochloric acid, water and aniline are mixed and cooled to 10 degrees C. Sodium nitrate aqueous solution is added to the mixed solution, the temperature of reaction system is maintained at 5 degrees C, stirred and reacted for 10-15 minutes. Sodium carbonate and sodium acetate are added to the reaction solution to obtain a diazonium salt solution. Ortho ethoxyphenol is dissolved in ethanol, cooled to 10 degrees C, and stirred. The solution is added to diazonium salt solution, reacted, water is added, and extracted with chloroform, concentrated, and dried to obtain 3-ethoxy-4-hydroxy azobenzene. 3-Ethoxy-4-hydroxy azobenzene, calcium oxide, sodium hydroxide, sodium iodide, bromo decane and dimethylformamide are added, reacted, extracted, concentrated, dried and recrystallized using ethanol to obtain 4-decyloxy-3-ethoxy azo benzene. 4-Decyloxy-3-ethoxy azo benzene, absolute ethyl alcohol, and Raney nickel are added, uniformly stirred, air is replaced with hydrogen, and reacted for 8-10 hours. The reaction solution is filtered, filtrate is concentrated, concentrated hydrochloric acid is added, solid is separated, filtered, and washed with water to obtain 4-decyloxy-3-ethoxyaniline hydrochloride. 4-Decyloxy-3-ethoxyaniline hydrochloride, potassium carbonate, ethoxy methylene ethylene dioxy diethyl maleate, and absolute ethyl alcohol are added and stirred at normal temperature for 10-12 hours, filtered, concentrated and re-crystallized to obtain 2-((4-n-decyloxy-3-ethoxy amino biphenyl)methylene) malonate. 2-((4-n-decyloxy-3-ethoxy amino biphenyl)methylene)malonate and diphenyl ether are added, reacted under protection of nitrogen at 250 degrees C for 4-6 hours, cooled to room temperature, the solution is poured into petroleum ether, precipitate is separated, and recrystallized to obtain 6-n-decyloxy-7-ethoxy-4-hydroxyquinoline-3-ethyl acetate.