Abstract: A method of manufacturing an LED illuminator is provided. At least one flat heat pipe (FHP) is provided, on which a flat surface is formed. A treating tool is provided to fix the FHP. A printed circuit layer is formed on the flat surface, which includes an insulated layer, a conductive layer and a solder mask layer spread on the flat heat pipe in order, to form solder portions. After that, solder paste is applied on the solder portions, and LED elements are disposed on the solder portions correspondingly. Finally, the FHP and the LED elements are passed through a reflow oven, to accomplish an LED illuminator. The FHP further has locating holes, which are used for orientating the FHP and connecting a heat-dissipating module by a concise assembling element.