The invention discloses a hood having a narrow gap for coal activation. The hood includes a hood body 1 formed by a non-metal temperature resistant material and an air passing device 2. The air passing device 2 is of a hollow structure, the surface of the air passing device 2 is provided with a plurality of protruding brackets 201, the air passing device 2 is closely attached to the inner wall ofthe hood body 1 through the protruding brackets 201, one end of the air passing device 2 is fixedly assembled in the hood body 1, and the air passing device 2 forms a gap type air passing channel withthe hood body 1. The air passing device 2 is further provided with a plurality of air passing through holes, the air passing through holes are located in the hood body 1, and the other end of the airpassing device 2 is further connected with a back flushing parallel flow device 3. According to the hood, not only can the blockage of the hood be effectively avoided, but also the hood has the characteristics of high temperature resistance, wear resistance and corrosion resistance.