An energy-saving and high brightness lighting fixture includes a light cover, a circular plate, a light-collecting lens, a housing body and an electronic device. The light cover is tubular with a plurality of heat sinks and a cooling tank. A circular plate is riveted with light cover's engaging portion, and an LED lamp is disposed on it. A light-collecting lens is disposed on the top of the light cover. A housing body's surface with fixture block and limiting strip, which housing body is inserted in the restricting groove by limiting strip and using fixture block to fix at ring groove of light cover. An electronic device has a main circuit board and at least one auxiliary circuit board, and electronic device can be inserted inside the light cover to reduce the volume and enhance the cooling effect.