The single-factor experiments and response surface methodology experiments were used to optimize KCl extraction processing of oil from grass carp viscera and oil's fatty acid composition and oxidation stability were analyzed. Experimental results showed that optimal processing of oil for grass carp viscera was : pH 8. 4,hydrolysis temperature 61. 28 ℃,hydrolysis time 41. 6 min,KCl content 4. 29%,liquid to solid ratio 1 ∶ 1,salting-out time 10min. By gradual regression fitting,the optimal predictive model was: Extraction rate( %) =- 1374. 0 + 102. 780A +11. 111B + 28. 912C + 26. 190D- 7. 0055A2- 0. 0715B2- 0. 3022C2- 10. 259D2+ 3. 4950AD- 0. 0862BC +0. 2895BD + 0. 3530CD. Use the above model,the predicted value was 55. 95%,and actual value was 55. 84%. By fatty acid analysis of refining fish oil,the results were: 13 kinds of fatty acid were determined,particularly palmitic acid,oleic acid and linoleic acid. The unsaturated fatty acids was at 74. 32% of the total fatty acids,saturated fatty acids was 25. 68%,essential fatty acids was at 24. 14%,ω-3 fatty acids( EPA DHA) was to 2. 94% of polyunsaturated fatty acids,and cis-fatty acids was to 99. 98% of unsaturated fatty acid. This indicated the fish oil had good nutrition value. Oxidation stability studies showed that oxidation induction time of fish oil was 0. 18h. This study provided a theoretical basis of fish oil extraction and storage.