The invention provides a waste rock belt conveying device. The waste rock belt conveying device comprises a base (1), a mounting rack (2), carrier rollers, a conveying belt (3), and a plow discharger (4), wherein the mounting rack (2) is arranged on the base (1), the carrier rollers are arranged on the mounting rack (2), and the conveying belt (3) is arranged on the carrier rollers with an adjustable conveying speed; the plow discharger (4) is arranged correspondingly to the conveying belt (3), the plow discharger (4) is provided with a material guide plate (5) which is arranged above the conveying belt (3) and a material throwing plate (6) which extends out from the material guide plate (5) to a filling area, and the material throwing plate (6) is provided with a material throwing inclined plane which extends upwards in an inclined mode. According to the waste rock belt conveying device, the problems that in the prior art, the filling efficiency of waste rocks is low and the filling compactness is low are solved.