The invention relates to an illumination lamp. According to the illumination lamp, lamp heads are internally provided with at least two color temperature light sources, and a shell is internally provided with a light control, a gear switch, a gear shifting assembly and a rotary knob; the gear shifting assembly is rotatably arranged on the shell, provided with a first light transmitting part for incidence of an external light source and connected with the gear switch; the rotary knob is rotatably arranged on the gear shifting assembly and can shield or partially shield the first light transmitting part. According to the illumination lamp, through the rotary knob arranged on the gear shifting assembly, the incidence of light rays or not in an end cover and the intensity of the light rays canbe controlled, and whether or not the illumination lamp is turned on can be selected according to demands; meanwhile, through the cooperation of the gear shifting assembly and the gear switch, the color temperature of the light rays emitted by the whole illumination lamp can be conveniently switched, in addition, a switch for controlling the switch-on and switch-off of the illumination lamp and the switch for controlling a color temperature gear position are integrated, the space of the whole illumination lamp can be saved, and the operation is facilitated. The invention further relates to abrightness control method of the illumination lamp.