Ultrasonic was employed to extract flavonoids from

Pinus massoniana

. Conditions for extraction were influenced by some factors

such as ethanol concentration

time and liquid-material ration

so they were optimized by response surface. Experimental results show the best conditions are as follows: the extracting time is 56 minutes

ethanol concentration is 40%

liquid-material ration equals 1:20

when the yield of flavonoids is 1.59%.This method is feasible for exploiting the material

and it provides the basis for its utilization. In the Response Surface experiment

compared with the factors of liquid-material ration and extracting time

ethanol concentration and power have greater influence on the extraction.