Cleaning device for inner wall of ventilation duct of smoke exhaust ventilator

The invention discloses a cleaning device for an inner wall of a ventilation duct of a smoke exhaust ventilator. The cleaning device comprises the ventilation duct, a climbing device and a working bin, wherein the ventilation duct is internally provided with the working bin, a rotating drum is arranged on the outer side of the working bin, the rotating drum is provided with two sets of fixed boxes, two fixed boxes are arranged in each set, a circular groove is formed inside each fixed box, a baffle is arranged inside each circular groove, one side of each baffle is provided with an elongated plate, when the rotating drum rotates, a hairbrush starts to rotate, meanwhile, cleaning liquid enters a water tank from a water pipe through a connecting pipe, the cleaning liquid is sprayed from a nozzle on the water tank outwards to clean the ventilation duct, under traction of the climbing device, cleaning liquid is sprayed to the ventilation duct firstly, then the hairbrush is used for brushing and washing, greasy di