Abstract: The present invention discloses an LED bulb and its lamp holder. The lamp holder is provided for guiding light sources. The light sources emitted from single LEDs in the LED bulb is diffused uniformly and merged with each other to provide good illuminations. A light guide pipe is integrated with an internal periphery of a transparent casing of the lamp holder and disposed at a position opposite to each single LED. A root portion of the light guide pipe has a larger external diameter at a position proximate to the transparent casing, and the root portion is extended to an end portion proximate to a position of the LED having a tapered external diameter to form a conical shape, such that the light source produced by each single LED can be passed through the corresponding light guide pipe and uniformly diffused to transparent casing, and then to the outside.