The blade type rotary rodless pneumatic cylinder is mainly composed of a stator, a rotor, blades and a housing. The stator has a gas distribution slot for intake and exhaust, the rotor is milled with a long slot, and the slot is equipped with blades. The two ends of the stator are covered with sealing covers, and the rotor and the stator are eccentrically installed. In this way, the blades sliding in the radial direction and the inner cavity of the housing form a rotating rodless air slide working chamber. The number of blades directly affects the efficiency of the rotary pneumatic rodless linear actuator, the starting performance and the stability of the movement. Usually there are 3 to 5 blades, and in special cases, up to 10.