Abstract: The measurement of electron energy spectrum is an important part of the performance test of electron accelerator. A new method named multi-layer absorption method to measure the electron energy spectrum was designed in this paper. It is based on the depth-dose curves method, which can be used in most irradiation accelerators, and the Monte-Carlo simulation and iterative algorithm were added so as to reconstruct the electron energy spectrum. This method is easy, accurate and needs no complicated equipment. This method was used to measure the spectrum of 6 MeV electron accelerator, and the good results were obtained. The results agree well with the measurement results of magnetic spectrometer in the error range, and it proves that the credibility is very high.