The invention discloses a desk lamp with the luminance capable of being automatically adjusted. The desk lamp comprises a lamp housing, at least three lamp tubes, a supporting pole, a light ray induction device, a lamp holder, a switch and a control module, wherein the control module is respectively connected with the light ray induction device, the lamp tubes and the switch, a power supply is connected with the control module through the switch and supplies power to the light ray induction device and the lamp tubes through the control module, all the lamp tubes are arranged in the lamp housing, the lamp housing is connected with the upper end of the supporting pole, and the lower end of the supporting pole is connected with the lamp holder. Because the number of the lamp tubes is at least three, the number of the lamp tubes needing to be turned on can be determined according to the luminance of the light rays of the environment, it can be guaranteed that the vision of a user is not affected, and the desk lamp is ingenious in conception, novel in design and worth popularizing.