The invention provides a measuring method in the molecular beam epitaxy (MBE) technology of measuring the thermocouple temperature of a corresponding source furnace when the source material is melted in a beam source furnace, which is characterized by that: the thermocouple temperature when the beam source furnace is heated is measured-power curve; the thermocouple temperature when the beam source furnace is cooled is measured-power curve; the corresponding temperature when the source material begins to melt on the power curve and the temperature when the beam source furnace is cooled, and the temperature when the source material begins to be solidified on the power curve are compared; then the thermocouple temperature of the corresponding beam source furnace when the source material begins to melt can be get. The invention utilizes the experimental phenomena of corresponding fluctuation of the power curve near the melting temperature and the solidification temperature in the course of heating and melting and cooling and solidifying the source material in the source furnace of the MBE equipment and precisely gets the thermocouple temperature of the corresponding beam source furnace when the source material in the beam source furnace begins to melt by analysis and comparison of the position of the fluctuation. The measuring method has important significance to the practical application of the MBE technology.