An illumination apparatus of light emitting diodes and method of heat dissipation thereof are provided. The present illumination apparatus is associated with a loop heat pipe (LHP) device. The LHP device includes a condenser communicating with an evaporator. The illumination apparatus includes a base having a plurality of light emitting diodes disposed thereon and a cover with a light exit enclosing the base. The evaporator is associated with the base and the condenser is associated with the cover. The heat generated from the light emitting diodes is conducted to the cover, and thereby dissipated away.