An LED lamp includes a base, an LED module having a plurality of LEDs mounted on a top of the base, and a light-guiding module fixed on the LED module. The light-guiding module includes a plurality of mounted plates and a plurality of inserted plates intersecting and engaging the mounted plates. The mounted plates and the inserted plates cooperatively define a plurality of cavities to receive corresponding LEDs therein for guiding and reflecting light generated by the corresponding LED in a predetermined manner.