The aim of this investigation was to examine the influence of extrusion on dietary fiber profile and the contentof bioactive compounds, rutin and quercetin in young sprout, whole seed, and matured stem of Tartary buckwheat.WSI(water soluble index) is increased by a function of both screw profile and process temperature, compared to control indifferent parts of Buckwheat. Also, WSI of ME is increased more than 5.2 times in grain, compared to that of control. Theeffect of precooking by extrusion on the dietary fiber profile of buckwheat flour was evaluated. Precooking by extrusion sig-nificantly increased SDF in flour, although in most cases extrusion decrease in TDF a little. The thermo-mechanical treat-ment undergone by the buckwheat flour during extrusion led to redistribute part IDF fraction to SDF, leading to an increasein the latter. The content of rutin was increased about two fold in extruded flour of sprout, compared to in control. Thisincrease maybe why these compounds are released from cell wall by high shear processing under high temperature.