According to the problems that drying quality was affected by the automatic grading and uneven distribution of grain in the inlet of material during drying process, the rotary shower distributing was researched to increase section area by 20～50 time, and the disturbance distributing was applied to maintain the cone-top angle of grain between 110°～170°. The distributing device combined rotary shower and disturbance was designed in order to increase transverse movement of grain on the top of dryer and to stabilize volume density of grain of cross section in dryer. The test of grain drying has showed that the distributing combined rotary shower and disturbance can control impurity content unevenness of cross section in dry storehouse less than 2% when grain moisture is less than 1%, which is a stable and reliable distributing device and better than that of throw tray or turntable widely used at present.