Abstract: In order to study the refined sardine oil ethyl esterification process, used refined sardine oil as raw material, based on the four univariate experiments:C₂ H₅ OH content, NaOH content, reaction time and reaction temperature, the regression model of ethyl esterification process was determined and the effects of various factors and their interactions on the yield of ethyl ester were also investigated using response surface analysis method. The results showed that the optimum conditions of ethyl esterification were as follows:C 2 H₅ OH content 60 g, NaOH content 1.2 g, reaction time 75 min, and reaction temperature 50℃. Under this condition, the yield of ethyl ester was 88.12% ±0.08%, and the ethyl esterification process was reasonable and feasible, which would provide some theoretical basis for the further development and utilization of ethyl ester refined sardine oil.