An LED illumination device includes an optical section at a front end thereof, an electrical section at a rear end thereof, and a heat dissipation section between the optical section and the electrical section. The optical section includes an LED electrically connecting with the electrical section, and a light output housing around the LED. The heat dissipation section includes a U-shaped heat pipe, a heat sink and a mounting seat. The heat pipe includes an evaporation section and two condensation sections extending backwardly from two opposite ends of the evaporation section, respectively. The condensation sections are inserted into the heat sink. The mounting seat bestrides on the evaporation section. The LED thermally connects with evaporation section via the mounting seat.