A lighting apparatus includes a lamp fixture; a bar-shaped lamp provided on the lamp fixture; a reflector, provided above the lamp fixture and below the bar-shaped lamp, including a first reflecting element, a second reflecting element opposite to the first reflecting element, and a reflector bottom connected to lower ends of the first and the second reflecting elements, so as to define a semi-closed internal space for containing the bar-shaped lamp, wherein the first and the second reflecting elements respectively have at least an outwardly-bent reflecting part for reflecting possibly much light out; a light sensor, clipping on the bar-shaped lamp, for detecting a change of ambient illuminance (LUX) and outputting a change signal; an electric power adjusting element, connected to the light sensor and the bar-shaped lamp, for receiving the change signal and accordingly adjusting the electric power of the bar-shaped lamp; and power connectors and emergency power connectors.