An air purifier and air processing method are disclosed. The air purifier includes an upper body (1), a lower body (2), an air process unit (3) which is arranged in the upper body (1) and used for processing air in the area ready for treatment, a mobile unit within the lower body (2) including a driving unit (7) and driving wheels (8), a control unit (6) for controlling operations of the air processing unit (3) and the mobile unit respectively, and an air quality sensor (4) used for detecting information values of air pollution. The signals of the air quality sensor (4) are transmitted to the control unit (6)； and then in the information storage sub-unit of the control unit (6), air pollution information values at the starting and ending points along two different straight-going directions of the air purifier detected by the air quality sensor (4) are stored； an information processing sub-unit of the control unit(6) processes the air pollution information values stored in the information storage sub-unit and determines the direction of pollution source.
