An LED lamp includes a cylindrical tube and two lamp holders fixed on two ends of the cylindrical tube. The cylindrical tube comprises a lampshade, a lamp plate, and a heat dispersing plate. The heat dispersing plate further comprises a base portion and two fastening portions. Two free edges of the base portion comprise two supports extending toward each other. The fastening portions are connected to the supports correspondingly, and the lamp shape and the lamp plate are fixed to the fastening portions correspondingly. Two lamp holders are fixed to opposite ends of the cylindrical tube, and each of the lamp holders comprises a hollow shell and a protrusion formed on an inner wall of the hollow shell. The protrusion resists against one end of the supports to prevent the lampshade from rotating relative to the heat dispersing plate.