The invention discloses a method for extracting buckwheat nutrient, and relates to deep processing of buckwheat. The method comprises the following steps of: (1) peeling the buckwheat, and crushing kernels; (2) leaching: connecting four reaction kettles in series, performing counter current leaching three times, putting the buckwheat powder into three reaction kettles, injecting a solvent into the No. 1 reaction kettle, heating the No. 1 reaction kettle to the temperature of between 85 DEG C and 95 DEG C, keeping the temperature for 40 minutes, introducing the leachate into the No.2 reaction kettle, injecting the solvent into the No. 1 reaction kettle and performing secondary leaching, heating the No. 2 reaction kettle to the temperature of between 85 DEG C and 95 DEG C, keeping the temperature for 40 minutes, performing primary leaching, transferring the leachate into the No.3 kettle, and performing third leaching; (3) drying: drying the third leached buckwheat powder for 40 minutes at the temperature of 100 DEG C without adding the solvent; and (4) extracting and reclaiming the leachate, and thus obtaining a finished product. The method is simple and convenient to operate, can be used for efficiently extracting the nutritional components in the buckwheat, is particularly high in extraction rate of rutin, and has an extremely great market value.