Abstract: A LED lamp tube is constructed to include a light-guide shade and a light source mounted inside the light-guide shade, the light-guide shade having a light guide layer, two mounting portions extended from the light guide layer at two sides for mounting, and protruding portions arranged inside the light guide layer and defining a respective light guiding groove for producing a respective luminous arc when radiated with light, the light source being a circuit board holding a plurality of light emitting diodes that are controlled to emit light onto the light guiding grooves of the protruding portions to further produce luminous arcs.