Abstract:Guyang buckwheat flour and Canada Windsor buckwheat flour were used as test material， which were milled by stone mill. The buckwheat flour was divided into four levels——whole grain flour（90 %）， com－ mon flour （75 %）， fine flour （60 %） and bran flour （40 %）. The flour samples were extracted from 70 % methanol at 70℃ for 4h for the evaluation of the antioxidant potential. The results showed that the TPC and TFC of buckwheat bran flour were highest while that of fine flour was lowest. The TPC and TFC of Guyang buckwheat bran flour were （3.80±0.05） mg/g and （5.49±0.20） mg/g， respectively. The TPC and TFC of Canada Windsor buckwheat bran flour was（4.10±0.09） mg/g and（5.45±0.05） mg/g， respectively. The TAC of buckwheat bran flour was obviously higher than whole grains flour， while the TAC of whole grains flour was significantly higher than fine flour. The graded flours have scavenging capacity of DPPH·，·OH and ABTS+·. The scavenging capacity ranked by descending order was bran flour>whole grain flour>common flour>fine flour. Guyang bran flour was higher on the ferrous ion chelating power， while Canada Windsor bran and whole grain flour was higher on that. In addition， there was a positively correlation between TPC， TFC， TAC， and free radical scavenging capacity.