The invention provides a heat supply furnace for coix seed drying, and a use method thereof. The heat supply furnace comprises a furnace body and a chain-plate conveyor, wherein an inner interlayer is arranged in the furnace body; an inner cavity of the furnace body is divided into an inner part and an outer part by the inner interlayer; a heat-insulation layer is laid outside the inner interlayer; a discharge end of the chain-plate conveyor stretches into the inner interlayer; a charge end of the chain-plate conveyor is arranged outside the furnace body; a leaked material collection groove is arranged at a floor below the charge end of the chain-plate conveyor; and a loader and a water supply device are further correspondingly arranged at the charge end of the chain-plate conveyor. The problems of unreasonable existing coix seed drying means, a too high fuel cost, serious pollution to environment, and food potential safety hazards due to a high possibility of pollution to products are solved. The invention belongs to the field of coix seed processing.