Abstract: A lighting device for a ventilating fan comprising a power pack module and a light-emitting module composed of a lighting louver and a radiator, wherein first positioning lugs projected out of a horizontal projection plane of the power pack module are formed on the top of the power pack module and fixed on the light-emitting module by screws; and a through hole which a cable, used for supplying power for a light-emitting unit, runs through is respectively formed on a side face of the radiator making contact with the power pack module and a side face of the power pack module making contact with the radiator. The lighting device for the ventilating fan further comprises hooks formed on the radiator and a second positioning lug formed on the power pack module, wherein the hooks and the second positioning lug are used for fixing the lighting device on the ventilating fan.