Provided is an air purification device, wherein a main body comprises air inlets at two sides. An air extractor at an air outlet draws in air; when entering, the air firstly passes through a negative high voltage wire to carry on a negative charge and be sterilized, and then is mixed with nanoscale water mist sprayed out from a spray pipe and enters a dust collection board; the water mist is electrolyzed from water in a water supply tank by an electrolyzer to generate alkaline water, which is supplied to a water storage tank and atomized by an ultrasonic atomizer prior to being ionized into nanoscale water mist by nano-electrodes so as to be sprayed out; and when air flows through a water mist stream, charged contaminative gases are mixed with the water mist, are separated from the air stream under the action of inertia and an attractive force from the electric field of the dust collection board, and collide with droplets to be captured, intercepted and collected, and when PM 2.5 and other dusts in the air are wetted by the droplets to condense into larger particles, gravity settling is realized, with particles with a certain weight falling into a waste water tank to be discharged out, and separated clean air is released out.