The invention discloses a multistage conveying belt control method and a multistage conveying belt control device based on preview control. The method comprises the steps of collecting material information of the feed end of the current stage of the conveying belt; calculating the optimal conveying speed of the next stage of the conveying belt according to the material information of the current stage of the conveying belt, and additionally, calculating the control rate of controlling to change the conveying speed of the next stage of the conveying belt to the optimal conveying speed on the basis of the preview control; and controlling the next stage of the conveying belt to adjust the conveying speed to the optimal conveying speed according to the control rate, so that the next stage of the conveying belt is operated at the maximum capacity. According to the method, the carrying capacity of a belt conveyor can be effectively used, and additionally, the speed of the conveyor is reducedto the current minimum value, so that the inherent power consumption of the conveyor is reduced, and the purposes of speed regulation and energy conservation are realized; the carrying time of materials on the conveying belt is effectively used, so that multistage speed regulation in the flow direction of the materials is realized, and the energy utilization rate of the whole belt conveyor systemis increased.