A light-emitting diode structure includes a base with a recessed portion, a light-emitting chip and a light-transmissive block. The light-emitting chip disposed in the recessed portion of the base and emits a light beam. The light-transmissive block disposed on the base covers the recessed portion and the light-emitting chip, so that the light beam emitted from the light-emitting chip is radiated outwardly via the light-transmissive block. The light-transmissive block is a flat-top multilateral cone including a bottom surface, a top surface, and several side surfaces connected to and located between the bottom surface and the top surface. A slot with a bottom portion is formed on the top surface of the light-transmissive block.