Abstract: Fish oil ethyl esters were prepared by a two-step process using fish oil fatty acid glyceride with high acid value. The first step was sulfuric acid-catalyzed esterification, followed by KOH-catalyzed transesterification. The appropriate process conditions were obtained as follows by the orthogonal test:for esterification, the reaction temperature was 70℃, the concentration of sulfuric was1.5%, the reaction time was 1h. For transesterification, the reaction temperature was 70℃, the concentration of KOH was 0.5%, the reaction time was 0.5h. Under the best conditions, the yield of ethyl ester is 92.5%.