A negative-pressure foam air-filtering purifier comprises a casing. The casing is divided into an upper casing and a lower casing; the upper casing comprises a left casing chamber and a right casing chamber; an air suction motor is arranged in the right casing chamber which is provided with an air outlet; a control panel is arranged in the left casing chamber. An ozone generator and an ultraviolet lamp are arranged in the lower casing, and the ozone generator, the ultraviolet lamp and the air suction motor are connected with the control panel which is further connected with a PM2.5 particulate matter probe, a harmful gas probe and an ozone spatial concentration remote-control switch. The harmful gas probe is arranged on the outer portion of the casing; the PM2.5 particulate matter probe is arranged on a carbon-fiber filter screen which is arranged on an air inlet formed in the lower casing. One side of the casing is connected with a negative-pressure generating chamber, an air inlet passage is arranged in the negative-pressure generating chamber, one end of the air inlet passage is connected to the lower casing, and the other end of the air inlet passage is connected with foaming stone. Exhaust outlets are formed in corresponding positions of the negative-pressure generating chamber and the upper casing and are provided with foam filtering screens.