The invention discloses a detachable rotary wear-preventive fluidized bed boiler blast cap including an air inlet pipe, an air inlet pipe cover plate, a rotation shaft, a screw rod nut and an external air cylinder. The lower end of the air inlet pipe is fixed on an air distribution plate hole, the upper end of the air inlet pipe is sealed with the air inlet pipe cover plate, and the side face of the air inlet pipe is provided with a plurality of small air outlet holes; the rotation shaft is welded above the air inlet pipe cover plate, the rotation shaft is processed with an internal thread, the thread is connected with the thread; the air cylinder is a hollow casing, the upper and lower ends of the air cylinder are end plates with holes, the hole of an upper end plate is in clearance fit with the rotation shaft, the hole of a lower end plate is in clearance fit with the air inlet pipe; a gap is existed between the upper surface of the upper end plate and the lower surface of a nut of the screw rod nut; and the lower section of the air cylinder is circumferentially provided with a circle of air outlet holes. The detachable rotary wear-preventive fluidized bed boiler blast cap overcomes the defects of inconvenience in replacement of a traditional blast cap, is convenient in disassembly and replacement, saves the replacement cost, enhances lateral mixing of materials, and has the advantages of being not easy to block, more wear resistant and durable and the like.