Abstract: The flash extraction method was employed to extract proanthocyanidins from Larch Bark.The effect of different ethanol volume fraction, raw material to liquid ratio, extraction time, extraction temperature on the extract rate of proanthocyanidins were investigated.The orthogonal experiment was conducted on the basic of the single factor experiment.The results showed that the optimum extraction conditions were as follows: volume fraction of ethanol of 60%, raw material to liquid ratio of 1∶25 ( g /mL) , extraction time of 4min, extraction temperature of 40℃. Under such conditions, the yield of proanthocyanidins was 11.42%.The proposed method was simple and fast with high extraction efficiency, which could be applied to extracting proanthocyanidins from Larch Bark.