Improved horizontal axial flow combine harvester

The utility model relates to an improved horizontal axial flow combine harvester which comprises a frame, a harvest platform, an engine, a driver's cab, a grain tank, a threshing roller, a threshing roller concave board, a horizontal axial flow roller, a horizontal axial flow roller concave board, a first long winch, a second long winch, a cleaning and sorting device, and a grass discharging device; wherein the threshing roller concave board is a concave board provided with holes; a front conveying device is provided below the threshing roller concave board; the grass discharging device comprises a grass discharging wheel and a grass guide, and the grass discharging device also comprises a pre-cleaning and sorting device which is composed of a guiding lip, a front air duct, a pre-cleaning and sorting vibration sieve and a quantitative grass collecting discharging device composed of a quantitative grass collecting discharging tank which can quantificationally collect and quantificationally discharge grass chaff. The utility model has the advantages of high working efficiency, little crushing of seeds, little loss of the seeds, no grass discharging rewinding, no small harvest platform clearing way influence, and no engine pollution; the grass discharging occupies a small operation area on the horizontal axial flow roller concave board, and stalks can be quantificationally discharged in heaps.