The invention belongs to the technical field of shortwall mechanical mining supporting equipment shuttle car transportation devices, particularly to a heavy-duty shuttle car transportation reducer. The heavy-duty shuttle car transportation reducer solves the problem of high heat and lower efficiency of transportation reducers of existing shuttle car transportation systems and comprises a casing, a coupling, a high-speed sun gear, a high-speed planetary assembly, a high-speed inner gear ring, a small bevel gear, a large bevel gear, a shaft, a low-speed sun gear, a low-speed planetary assembly, a low-speed inner gear ring and an output shaft. The heavy-duty shuttle car transportation reducer is high in efficiency and high in reliability, improves the heavy-duty starting capacity of a shuttle car transportation device, enhances the reliability of the shuttle car transportation device, prolongs the service life of the shuttle car conveying device, achieves high power density, is applicable to the transportation system of a heavy-duty shuttle car as well as the transportation system of a common shuttle car and has a wide application prospect.