Abstract: In the present study, the total lipids from Schizochytrium sp. were ethylated by immobilized lipase and ethyl esters highly enriched in C22∶6 n-3 (DHA) was obtained through molecular distillation. The effect of temperature, reaction time, substrate ratio, and enzyme dosage on enzymatic ethylation was investigated. Under optimum reaction conditions (reaction temperature 40℃, reaction time 24 h, substrate ratio 10∶2, Lipozyme 435 dosage 6%) , immobilized lipase had good operational stability. Ethyl esters with no less than 80% DHA was obtained via molecular distillation, and the yield of DHA ethyl esters could be significantly improved by multistage molecular distillation and recycle of light fractions.