Abstract: In order to set up the optimal method and the technology of fish oil extracted from the viscera of silver carp and make the most use of the resource of silver carp, fish oil was extracted from the viscera of silver carp by a modified potassium hydroxide hydrolysis method and enzymatic hydrolysis method respectively.The extraction rate and the physicochemical properties of fish oil by two methods were compared.Results showed that the optimal process parameters of potassium hydroxide hydrolysis were as follows:1.5 ∶1 ratio of water- viscera, 5% potassium nitrate, 70℃ for hydrolysis temperature, pH7.5, 40min for hydrolysis time and 15min for salting-out time.Under the condition, the extraction rate of fish oil was 87.49%.The optimal process parameters of enzymatic hydrolysis were as follows:pH7, 50℃ for enzymolysis temperature, 2.5h for enzymolysis time, 1.5% enzyme dosage, 1.5∶1 ratio of water-viscera.The extraction rate of fish oil was 90.33% under the condition.The physical and chemical indexes of oil extracted by potassium hydroxide hydrolysis and enzymatic hydrolysis were as follows respectively:acid values were 14.58mg KOH/g and 9.23mg KOH/g, peroxide values were 3.82mmol/kg and 3.47mmol/kg, iodine values were 123.93g I2 /100g and 127.48g I2 /100g, water and volatiles were 0.48% and 0.32%, impurities were 0.13% and 0.34%.The physical and chemical indexes of fish oil through enzymatic hydrolysis were better than those extracted by potassium hydroxide hydrolysis except impurities.So enzymatic hydrolysis was the better extraction method.