Abstract: In order to optimize the ultrasonic extraction process of pomegranate seed oil and analyze the composition of fatty acid in the seeds, the optimal extracting conditions were studied with the orthogonal experiments on the basis of single-factor experiments. And composition of the PSO was analyze with GC-MS method. Experiment results show that the optimum conditions are as follows:particle size of material 200 screen mesh, extractant n-hexane, reaction temperature 50℃, time 60min, ultrasonic power 80W, solid/liquid ratio l:12(g/mL). Under the conditions, the oil yield ratio could reach17.97%, and 12 kinds of fatty acid were checked out from Huili's pomegranate, 11 from Shandong's, 10 from Yunnan's. The content of unsaturated fatty acid in these three kinds of pomegranate is relatively higher, and the percent of Punicic acid are all above 61%.