The probable reason of skeletal muscle atrophy would be insulin / Akt signaling pathway block-mediated abnormity of protein metabolism in skeletal muscle cell. n-3 polyunsaturated fatty acids（n-3 PUFA） can act on various sites inside and outside skeletal muscle cells to maintain the pathway. ALA is a plant-derived n-3 PUFA， which is more effective on direct stimulation of secretion of insulin via GPR40 on the membrane of pancreatic beta cell. EPA and DHA are marine fish-derived n-3 polyunsaturated fatty acids（n-3 PUFA）， which can maintain the activation of Akt pathway in skeletal muscle cell and have shown beneficial effects on insulin sensitivity. Ralated researches were reviewed to understand the role of n-3 PUFA in prevention of abnormal proteolysis in skeletal muscle cell and to previde new ideas for the intervention of skeletal muscle atrophy by dietary nutrients.