The invention relates to a dust monitor. The dust monitor comprises a damping support, a laser box power supply, a control console, a laser box body, a control wire, a damping foundation support, a rotating platform, a laser platform, an alignment laser tube, a beam collection laser tube, a conducting wire frame, a groove, an alignment receiver, a laser hole, a damping shell, a dust absorption filter net sleeve, an upper passage, a warning light, a lower passage, a temperature sensor, a humidity sensor, a signal receiving box body, a front panel, an opening, a guide rail platform, a measuring receiving tube, a lens, a slide chute, a calibration receiving tube, an optical fiber, a dust collection valve, a processor, a photoelectric diode, a monitoring microcomputer, a power supply box, a battery pack and a conducting wire. The dust monitor has the beneficial effects that (1) the complexity of the measurement requirement is alleviated, the working reliability and stability can be improved, and the dust monitor is suitable for high-dust, high-temperature and high-vibration wooden product processing field; (2) the attenuation and loss of an optical signal in a worse monitoring environment can be prevented; (3) the apparatus can be protected by virtue of feedback brake and warning; and (4) the application range of the product can be enlarged.