To study the extraction conditions for Proanthocyanidins assited by ultrasonic wave from Garcinia mangostana L peel.Effects of ultrasonic power,solid-liquid ratio,ethanol concentration,and extraction time and extraction temperature on the extraction rate were studied by single factor test.Then the optimum extraction condition was optimized by L9(34)orthogonal test.The influence order of these factors on the extraction rate of proanthocyanidins was:ethanol concentration(B)>extraction temperature(C)>solid-liquid ration(A)>extraction time(D).The optimal extraction condition was:solid-liquid ratio 1:30(g:mL),the concentration of ethanol 60%,the extraction time 30 minutes at 50℃.Under the optimum conditions,the yield of proanthocyanidins in Garcinia mangostana L peel was 15.61%.