Ultrasound assisted extraction of proanthocyanidin from rapeseed hull using ethanol as the extraction solvent was studied. Based on the single factor tests of ethanol volume fraction, extraction time, liquid-solid ratio and ultrasound power, the optimum process were evaluated by Box-Behnken central composite experimental design and response surface methodology analysis. The results indicated that ethanol volume fraction 62.9%, extraction time of 20.8min and liquid-solid ratio of 25mL/g were found optimum. Under these optimized conditions, the experimental value of proanthocyanidin extraction yield 5.05mg/g, in good agreement with the predictive value 5.02mg/g. Therefore, the ultrasound-assisted extraction of proanthocyanidin from rapeseed hull using response surface methodology is very reliable.