Abstract: The present invention provides a system and a method of detecting a sublimation point, preferably applied to organic molecules. The system of detecting a sublimation point comprises: a heater, a capillary device, a vacuum pump, an ultraviolet light source, a photography device, a digital vacuum meter and a needle valve. The system of detecting a sublimation point is suitable for detecting the sublimation point of an organic light emitting molecule such as tris(8-hydroxyquinolinato) aluminum (Alq3) and tris(phenylpyridine) iridium (Ir(ppy)3). The needle valve can be used for controlling air pressure to measure the sublimation point under different pressures. Advantageously, the required quantity of organic molecules can be below 1 mg, thus not only saving the organic molecules, but also detecting the sublimation point without contaminating apparatuses.