Abstract: A ceiling mounted air purifier is disclosed, comprising a winnower having two winnower air entrances on two sides thereof, a winnower air exit, and a windshield; a base having a recessed groove below a middle thereof for accommodating the winnower, two air inlet passages disposed on two sides of the recessed groove respectively, and an integrated air exit disposed at a top thereof for tightly connecting the winnower air exit of the winnower by the windshield; a back shell disposed at a bottom of the base to position the winnower in the recessed groove and seal bottoms of the two air inlet passages; two air inlet filters respectively inserted into exits of the two air inlet passages and corresponding to the two winnower air entrances; a filter cartridge container disposed on the winnower air exit; and a front shell disposed at the top of the base to release filtered air.