An improved LED assembly comprises a frame and a circuit substrate. The frame has a slot, which has an opening on the upper surface of the frame. An elongated inverted L-shaped structure is formed on either side of the opening, and one or more conductive strips are formed on the inner side of the elongated inverted L-shaped structure. Therefore, electricity may be supplied to the conductive strips of the frame. In assembly, the circuit substrate is slid into the slot of the frame so that each of the conductive strips of the circuit substrate is engaged with the corresponding conductive strip of the frame. Therefore, electricity from the electric source may be fed from the source through the conductive strip of the frame and the conductive strip of the circuit substrate and then to the light-emitting units so that each of the light-emitting units may be powered up.