The air discharged by the negative pressure fan reduces the indoor air pressure, and the indoor air becomes thinner, forming a negative pressure area, and the air flows into the room because of the air pressure difference compensation. In the practical application of the industrial factory building, the negative pressure fan is centrally installed on one side of the factory building, the air inlet is on the other side of the factory building, and the air is blown by convection from the air inlet to the negative pressure fan. In this process, the doors and windows near the negative pressure fan remain closed, forcing the air to flow into the workshop by compensating the doors and windows on one side of the air inlet. The air is lined up and flows into the workshop from the air intake in an orderly manner, flows through the workshop, and is discharged from the workshop by the negative pressure fan. The ventilation rate can be as high as 99%. Through the specific engineering design, according to the need to design ventilation speed and wind speed, high heat, harmful gas, dust smoke can be quickly discharged from the workshop, and the problem of poor ventilation can be solved at one time.The effect of ventilation can be achieved within a few seconds of turning on the fan.