The invention discloses an air ventilation purifier and a ventilation filtering technical method. The air ventilation purifier comprises a preliminary filtering net, an air intake
pipe, an air internal and external circulation switching valve; a filtering device comprises a U-shaped filtering cylinder, a U-shaped filtering element, an air ventilator, an intelligent switching controller and an airoutlet
pipe; and an exhausting device comprises an air exhausting
pipe, an air exhausting valve and an air exhauster. One end of the air intake pipe communicates with the outdoor air, and the other end of the air intake pipe is connected to an
indoor air purifier; the exhausting pipe is arranged at the place of the farthest distance from an opposite angle of a port of the
indoor air outlet pipe; two ends of the air exhausting pipe correspondingly communicate with the outdoor air and
indoor air; and when the air ventilation purifier is started, the outdoor air enters the U-shaped filtering cylinder through the air intake pipe, the outdoor air is filtered by the U-shaped filtering element and enters the room through the air outlet pipe, the outdoor air is breathed by people when flowing indoors and then discharged outdoors through the air exhausting pipe. The principle of the purifier is that the outdoor air is purified and then introduced indoors for
air exchange, and the defect that atraditional
air purifier can only filter air but not replace the indoor air is solved.