Abstract: Microwave extraction of total isoflavones from P.Lobata powder was studied. The result of quantitative analysis of total isoflavones indicates that under the condition of 77% alcohol, the ratio of solid to liquid is 1∶14, the temperature was at below 60℃, and the solution was treated at regular intervals for three times, the extracting rate of total isoflavones was more than 96%. Compared to the traditional extraction, microwave extraction not only provides higher production rate but also has the advantages of being fast and energy saving.