Negative pressure fan is the newest type of ventilator, belonging to Axial fan, because it is mainly used in negative pressure ventilation and cooling engineering, called negative pressure fan. The negative pressure ventilation and cooling project includes two aspects of ventilation and cooling, and the ventilation and cooling problems are solved simultaneously. The negative pressure fan also applies to the positive pressure type curtain environmental protection air conditioning, the positive pressure sends the wind, the positive pressure and so on the field. The negative pressure blower has the characteristics of large volume, Super Gale Channel, Super Gale Leaf diameter, super large exhaust air, ultra-low energy consumption, low speed, low noise and so on. The negative pressure fan from the structural material mainly divides into the galvanized plate square negative pressure fan and the FRP trumpet type negative pressure fan. In the market all galvanized plate square negative pressure fan structure and technical parameters are basically consistent, negative pressure fan model classification will be detailed. FRP Trumpet-type negative pressure fan is divided into belt-type and straight-knot type from different transmission mode, and the type of negative pressure fan will be described in detail. Domestic negative pressure blower manufacturers are mainly distributed in Guangdong, Shandong, Jiangsu, Fujian and other places.