Negative pressure fan outward air pressure drop, indoor air thinning, forming a negative pressure zone, air due to pressure differential compensation into the room. In the practical application of industrial plant, the negative pressure blower is installed on one side of the plant, and the air inlet is on the other side of the factory room, and a convection wind is formed from the inlet to the negative pressure fan. In this process, the doors and windows near the negative pressure fan remain closed, forcing the air to be compensated into the workshop by the side doors and windows of the inlet. Air platoon, orderly flow from the inlet to the workshop, flow from the workshop, from the negative pressure fan out of the workshop. Ventilation is complete, efficient, ventilation rate can be as high as 99%. Through specific engineering design, according to the need for ventilation speed and wind speed, any high fever, harmful gases, dust smoke can be quickly discharged from the workshop, any problem of ventilation can be a one-off solution. The ventilation effect can be achieved in a few seconds from the opening of the fan.