Graphene oxide (GO)-assisted ethanol reflux extraction (GERE) was used to extract flavonoids in bamboo leaves. The parameters of GERE were optimized by the fractional factorial?response surface method, and the extraction mechanism was analyzed. The results showed that the optimal conditions were ethanol 80%(?), ratio of liquid to solid 17 mL/g, addition GO 1.5 mg/g at 82℃ for 86 min. Under optimized conditions, the yield of total flavonoids was 88.4%, about 10.6% higher than ethanol reflux extraction (ERE). GO can lead to the destruction of the cell wall, the reduction of the crystallinity and the grain sizes of cellulose, which improved the extraction rate of bamboo leaves flavonoids. Thus, it was indicated that GERE method is an efficient, green, novel method for extraction of bamboo leaves flavonoids.