The invention relates to a carrier roller pneumatic rubber scraping device of a belt conveyor. The carrier roller pneumatic rubber scraping device comprises a carrier roller, a mounted bearing, a scraper, a scraper seat, a rodless cylinder, a cylinder support, a proximity switch, a balancing weight, a glue blocking plate and the like, wherein the carrier roller is fixed to a machine frame of the conveyor through the mounted bearing, the rodless cylinder is fixed to the machine frame of the conveyor through the cylinder support and the rubber blocking plate, the axis of the carrier roller is parallel to the axis of the rodless air cylinder, the middle of the scraper seat is fixed to a sliding block of the rodless cylinder, the scraper and the balancing weight are installed at the two ends of the scraper seat, the scraper makes contact with the outer circle of the carrier roller, the contact pressure can be adjusted by increasing or decreasing the balancing weight, when the belt conveyor runs, the scraper can continuously remove rubber covering the carrier roller along with axial reciprocating motion of a sliding block on the rodless cylinder, the rubber blocking plate with the inverted-V-shaped cross section is installed above the rodless cylinder, and normal work of the rodless cylinder can be guaranteed, so that heavy physical labor of workers is relieved, the operation cost is reduced, and the production efficiency is improved.