The invention discloses a door and window ventilation mullion. The door and window ventilation mullion comprises a ventilation mullion main body, wherein a reinforced lining is arranged in the ventilation mullion main body; an air inlet cavity, a first middle cavity, a second middle cavity, an air filtering material cavity, a first ventilation grid, a second ventilation grid and a third ventilation grid are arranged in the ventilation mullion main body; an outdoor air outlet is formed in the outer side of the air inlet cavity; a vertical rainproof louver is arranged in the air inlet cavity; sound-insulating cotton is arranged in the first middle cavity; a sliding grid sealing plate is arranged in the second middle cavity; a control switch is arranged in the air filtering material cavity; an indoor decorative cover is arranged on the outer side of the air filtering material cavity; an indoor air inlet is formed in the indoor decorative cover; an air filtering material is arranged on the inner side of the indoor air inlet; and a glass stop block and a glass stop are arranged on the two outer sides of the ventilation mullion main body respectively. The door and window ventilation mullion serving as a ventilation mullion is applied to doors and windows, can achieve the bearing, reinforcing, grid dividing and decorative effects of the door and window mullion, and also can realize micro-ventilation, fog and haze resistant, rainwater-proof, anti-mosquito and noise-reducing functions.