To research the best optimum parameters of yeast fermentation, provides reference for the development of buckwheat health fermented food. Buckwheat was selected as raw material, which was fermented by AnQi yeast, and the total content of flavonoids was chosed as the evaluation indexes. Through the single factor test and orthogonal test, including water addition, fermentation temperature, inoculation quantity and fermentation time, the optimal fermentation technology was gotten. The optimal fermentation conditions were: water addition 75%, fermentation temperature 32 ℃, inoculation quantity 0.5%, and fermentation time 6 h. Under the conditions, the total flavonoids content was from 4.895 mg/g to 5.314 mg/g, while, the quercetin content decreased from 1.468 mg/g to 1.099 mg/g.