The utility model provides a single cycle grain drying machine, it includes support (1), outer cylinder (2), flight device, feed hopper (7), outer cylinder rotating device, inner core - tube (3), be used for carrying drying grain's conveyer (8) and air supplying module, the one end of inner core - tube (3) is equipped with hot -blast entry, and the stack shell of inner core - tube (3) is equipped with a set of vent, be equipped with grain entry, grain export and air outlet on outer cylinder (2), the utility model provides a single cycle grain drying machine, air inlet mode adopt the one end air inlet, inner tube uniform air distribution's in to grain stoving passageway mode, and hot -blast hot blast blowpipe apparatus heat conversion is high, and it is remarkably productive to let in the postbaking of grain drying -machine, sets up waterfall's flight outside on the inner wall of cylinder, and the grain that constantly turns provides the plot ratio of grain drying -machine greatly, and can the plot ratio reach 35 40%, grain stoving effect is even more ideal, has fine practicality and spreading value.