Ethyl ester of conjugated linoleic acid was synthesized in batch reactor. The reaction was catalyzed by sulfuric acid, phosphoric acid or p-toluenesulfonic acid. Orthogonal design was adopted to determine reaction conditions. Sulfuric acid and p-toluenesulfonic acid showed strong catalytic activity while phosphoric acid proved to be ineffective. Optimal process conditions were obtained as follows. Sulfuric acid was the preferred catalyst. Mole ratio of conjugated linoleic acid to anhydrous alcohol was 1:6. Reaction temperature was 76 degreesC and reaction time 1 h. Weight of sulfuric acid was 2.5% the weight of conjugated linoleic acid. Yield of the product reached 75%. Weight percent of ethyl ester of conjugated linoleic acid in the product was 77% -82% .