By analyzing the movement of material in the sweep auger, the conclusion of the basic requirements of auger’s efficiently transporting grain was drawn, and the formulas of elemental parameters of axle diameter of auger，its pitch and helix angle and etc. were obtained, from which the better structure parameters of sweep augers suitable for counterflow dryer were got. The characteristics of sweep augers as well as the grain transporting column curves of auger flights with the equal pitch keeping the bin top level after removing grain was analysed. It is considered that the manufacture of popular sweep augers with variable pitch is difficult. Finally the auger of equal pitch with combining structure of straight and taper types was developed. Through applying them to the 5HPN flatbed counterflow dryer, it is indicated that the research conclusion meets the actual requirements completely.