The invention discloses a discharge opening which comprises an outer shell and an inner shell. The outer shell and the inner shell are of a conical structure and are shaped like funnels which are mutually nested. A ring-cone-shaped air cavity is formed between the outer shell and the inner shell. The upper end and the lower end of the outer shell are each provided with a flange plate. At least one air inlet is formed in the upper portion of the side face of the outer shell. The conical structure of the inner shell is formed by folding an upper cone section to be a lower cone section; the taper of the upper cone section is larger than that of the lower cone section; the bottom edge of the lower cone section is lower than the air inlets, and flow guide plates which extend out to be fixedly connected with the outer shell are evenly distributed on the periphery of the lower cone section. A material area communicated with the air cavity is formed on the lower portion of the outer shell. The discharge opening is powerful in fluidization function and does not need special maintaining in usage.