The invention discloses a high-efficiency environmental-friendly belt conveyor cleaning device which comprises an ultrasonic cleaning device arranged on a belt conveyor and used for cleaning, as well as a pollution discharge channel, wherein the ultrasonic cleaning device further comprises a transducer, an ultrasonic generator, a storage tank, a cleanout fluid ejection pipeline and a work head; the transducer converts electric energy into mechanical energy; the ultrasonic generator generates a high-frequency electric signal; the work head is arranged at one end of the cleanout fluid ejection pipeline. The high-efficiency environmental-friendly belt conveyor cleaning device disclosed by the invention is simple in structure, reasonable in design and high in practicality. Compared with a pure water pressure flushing device, the device disclosed by the invention does not need high water pressure, only cleanout fluid needs to be flushed onto the belt surface, extra friction obstruction is not produced to the belt conveyor so as not to cause damage, and the cleaning effect is good. Because the ultrasonic wave is high in frequency, short in wavelength and high in penetrating power, any tiny position of the belt can be completely cleaned, a striking effect can be achieved, the efficiency is high, the service life of the belt conveyor is greatly prolonged, and the environmental pollution is reduced.