Abstract: Fish oil was extracted by microwave assisted method with lyophilizes tilapia as raw material of the test. The optimum extraction processes were determined by single factor and orthogonal experiment. Fatty acids compositions of fish oil extracted from the whole fish and all parts(head,tail,bone,muscle,skin and gut)were analyzed by GC. According to the national standard,the physical and chemical indexes of the whole fish and its parts were detected. The results showed that fish oil extracted optimum process conditions by microwave assisted method for hexane as the best solvent,solid-liquid ratio was 1:10 (g/mL),microwave power was 100 W for 10 min. The highest extraction rate was 29.17%±0.13%. The fatty acids of oil extracted from the whole fish and all parts were mainly composed of palmitic acid(20.98%~23.20%),oleic acid(19.06%~25.96%)and linoleic acid(10.38%~15.74%). In the all parts,muscle had the highest content of DHA+EPA(3.29%±0.07%),next was tail(3.10%±0.03%). The fish oil physical and chemical indexes all conform to the national standard. Therefore,the quality of fish oil extracted by microwave assisted method would be better.