The objective of this study was determined the change of rutin content in buckwheat through extrusion process. An extruded product was prepared by changing the screw speed(180, 220, 260 rpm), barrel temperature(80, 100, 120℃), and moisture content(15.0, 22.5, 30.0%). The rutin content was significantly influenced by screw speed and barrel temperature. It was decreased with the increase in screw speed and barrel temperature. Rutin content in buckwheat was not decreased by autoclave-heating buck-wheat, the thermal stability of rutin was confirmed.