The invention provides a lift illumination system which is one used for illuminating the upper surface of a top plate of a lift car during maintenance inspection. The lift illumination system has a photodetector for detecting the illuminance of the upper surface of the top plate of the lift car; a lift car upper illumination part capable of illuminating the upper surface of the top plate of the lift car; and a control unit which judges whether illuminance detected by the photodetector is lower than a predetermined value under the circumstance that the running mode of the lift car is switch to an inspection running mode through an inspection switch arranged at a lift taking position of a reference layer, the lift car is located in an entering position where operating personnel can enter into the top plate of the lift car from the lift taking position for waiting, and a door arranged at the lift taking position is open, and enables the upper illumination part of the lift car to be turned on when judging the illuminance to be lower than the predetermined value.