The invention discloses a disc type arc air bag polishing head, and relates to polishing tools. The disc type arc air bag polishing head is capable of achieving double-edge supporting and positioning, improving dynamic balance performance and designing inertia according to application scenarios, good in rigidity and high in polished surface quality. The disc type arc air bag polishing head is provided with an annular air bag, a disc-shaped hub, an annular air bag support, air bag tire beads, an airtight layer and a tire bead seat. The annular air bag is directly arranged on the annular air bag support in an injection molding mode and is pressed into a groove of the disc-shaped hub, a polishing material layer is arranged on the outer surface of the annular air bag, the air bag tire beads are arranged on the two sides of an opening of the annular air bag, and the air bag tire beads are attached to the tire bead seat. An air inlet channel is formed in the disc-shaped hub, an air inlet is formed in the short shaft end of the disc-shaped hub, and the air inlet channel is connected with an inner cavity air inflation opening of the annular air bag. The airtight layer is attached to the groove of the disc-shaped hub, and bearings are mounted on steps at the two ends of a hub shaft of the disc-shaped hub. Gas pressure is changed, so that the polished surface quality and the machining efficiency are adjusted, and the balance performance and the positioning accuracy of the air bag polishing head are improved.