A light source device includes a first heat dissipation structure, an LED module, a heat energy convertor and a fan. The first heat dissipation structure includes a heat dissipation base, a first fin group attached on a top surface of the heat dissipation base. The LED module is attached on a bottom surface of the heat dissipation base of the first heat dissipation structure. The heat energy convertor is thermally connected to the heat dissipation base of the first heat dissipation structure through heat pipes, and configured for changing heat energy generated by the LED module into kinetic energy. The fan is disposed over the first fin group and driven by the heat energy convertor.