Desktop ASE light source is an amplified spontaneous emission light source designed for passive optical component testing, spectrum analysis. Its design is based on pump rare-earth doped fiber realized with spontaneous emission on semiconductor laser diode and part light feedback and controlling technology. It features high output power, wide spectrum, low polarization and good power stability and average wavelength stability, which is widely used to fiber sensor system, testing and imaging. Desktop ASE light source can provide  different levels larger output power. In employing of precise level-II refrigeration principle and photoelectricity separating structuring designing technology, it can effectively improve the short-term and long-term stability on output power.