Abstract: Objective: To explore a new method of preparation of pomegranate ellagic acid. Methods: The effect of hydrolysis temperature ( pressure) , hydrolysis time and sulfuric acid concentration ( v/v) on ellagic acid yield were studied respectively with high pressure steam sterilizer as the reactor, and also the process parameters were optimized. Results: The highest ellagic acid yield was 3.09% under the optimum conditions of hydrolysis temperature ( pressure) of 115 ℃ ( 169 k Pa) , hydrolysis time of 2 h, sulfuric acid concentration of 5% ( v/v) , and was increased by 25.10% compared with the atmospheric pressure.Conclusion: Under the condition of high temperature and high pressure, granatanine extracten by hydrolysis method of preparation of ellagic acid efficiency was higher.It provided technical basis for the improvement of production process.