Abstract: An LED lamp tube comprises a heat-dissipating ring, presented as an annulus having a ring base, an inner ring plate, and an outer ring plate; a transparent ring, an inner edge thereof being bonded to the inner ring plate of the heat-dissipating ring, and an outer edge thereof being bonded to the outer ring plate of the heat-dissipating ring; and an LED emitter including at least two circuit substrates connected to each other to form a ring, LED dies bonded to each of the circuit substrates, transformers, and a connection terminal, the LED emitter being further bonded between the heat-dissipating ring and the transparent ring. Thereby, the objectives of shape diversity, material saving for circuit substrates, heat-dissipation enhancement, and easy replacement of lamp tubes may be achieved by the LED lamp tube of the present invention.