The invention relates to the technical field of semiconductor illumination and photoelectric testing, and provides a method and device for measuring the service life of an LED. The method comprises the steps of acquiring measurement data of a test sample under a first condition; fitting a first changing curve of changes of internal quantum efficiency of the test sample at a preset temperature following the changes of a plurality of preset current corresponding to the preset temperature; according to the first change curve of the internal quantum efficiency of the test sample at each preset temperature, finding a corresponding preset temperature when the internal quantum efficiency reaches a preset threshold, and setting the preset temperature as a test temperature for determining the service life of the LED. In the method, the acquisition of the measurement data of the test sample is simple in operation and short in testing time, the whole test can be completed in one day or several hours, and the test efficiency is greatly improved compared with 7-10 days of the prior art.