The invention discloses a device for precisely detecting, alarming and removing sundries of an air conditioner outdoor unit. The device comprises an air speed detecting device, a Zigbee module, a central control device, a sweeping device and an alarming device, wherein the air speed detecting device is connected with the Zigbee module; the Zigbee module is connected with a signal input end of the central control device via a Zigbee wireless network; a signal output end of the central control device is connected with the alarming device; a control end of the central control device is connected with the sweeping device; the air speed detecting device is arranged on the inner side of an air conditioner outdoor unit condenser and comprises a plurality of air speed instruments which are arranged as a matrix; the sweeping device is arranged on the outer side of the air conditioner outdoor unit condenser and comprises a spiral reciprocating type mechanical traveling arm brush and a motor. The invention also discloses a method for precisely detecting, alarming and removing sundries of an air conditioner outdoor unit. The device for precisely detecting, alarming and removing sundries of the air conditioner outdoor unit is simple in principle and powerful in implementable functions; the operation effect of the air conditioner is improved; the service life of the air conditioner is prolonged; the safe and stable operation of a machine room is guaranteed.