The invention discloses a tobacco leaf internal circulating device of a four-layer tobacco loading bulk curing barn. The tobacco leaf internal circulating device comprises a controller, driving motors, rotary shafts, longitudinal conveyor belts, transverse conveyor belts and blocking columns. The tobacco leaf internal circulating device has the advantages that the running speeds of the various driving motors can be independently regulated and controlled by the controller in tobacco loading and tobacco leaf curing procedures, and the longitudinal conveyor belts and the transverse conveyor beltscan be driven by the rotary shafts under the effects of the driving motors to run according to certain directions; the blocking columns are arranged on the various conveyor belts and are used for fixing tobacco stems and tobacco leaves and driving the tobacco stems and the tobacco leaves to run along with the conveyor belts, the transverse conveyor belts and the longitudinal conveyor belts are sequentially connected with one another, and accordingly the tobacco leaves can move in a tobacco loading chamber according to an S-shaped path in a circulating manner; tobacco leaf states in differentcuring periods are combined with one another, the circulating running speeds of the tobacco leaves in the tobacco loading chamber can be regulated and controlled, the problem that existing tobacco leaves at different locations are positioned in uneven temperature and humidity fields in curing procedures can be effectively solved, accordingly, the integral curing quality of the tobacco leaves can be guaranteed, the amount of labor used in tobacco loading procedures can be reduced, and the labor intensity in the tobacco loading procedures can be relieved.