Automatic uniform distribution apparatus and automatic adjusting method for threshed material from harvester

An automatic uniform distribution apparatus for a threshed material from a combine harvester, the automatic uniform distribution apparatus comprising a tangential flow threshing and separating device, an axial flow threshing and separating device, a chaff screw conveyor and a vibrating sieve, wherein a shaking plate and a return plate are disposed above two ends of the vibrating sieve, the shaking plate is located below the tangential flow threshing and separating device, and the return plate is located below the axial flow threshing and separating device and the chaff screw conveyor, the shaking plate comprises a shaking plate flow guiding mechanism mounted on a side thereof onto which the threshed material from the tangential flow threshing and separating device falls, a shaking plate threshed material detecting device is mounted at a discharge port of the shaking plate, the return plate comprises a return plate flow guiding mechanism mounted on a side thereof onto which the threshed material from the axial flow threshing and separating device falls, a return plate threshed material detecting device is mounted at a discharge port of the return plate, the shaking plate threshed material detecting device and the return plate threshed material detecting device are both connected to an input terminal of an on-line detection controller, and the on-line detection controller is configured to control action processes of the shaking plate flow guiding mechanism and the return plate flow guiding mechanism.