Abstract: To investigate the evolution law of the inherent frequency characteristics of rocks during the fracturing process, a uniaxial compression acoustic emission experiment on siltstone was carried out. The dominant frequency and fundamental frequency signals of the acoustic emission signals were extracted using the Fast Fourier Transform (FFT) method, and a parameter T for comprehensively characterizing the spectral characteristics of the acoustic emission signals was proposed, namely the ratio of the dominant frequency to the fundamental frequency. The results show that the dominant frequency distribution shows a dynamic belt characteristic of "wide−narrow−wide", and its frequency band quantity changes nonlinearly first decreasing and then increasing; the fundamental frequency distribution range shows a stepwise expansion, and the newly added medium/high frequency signals in the later stage can be used as a characteristic of fracture early warning. The dominant frequency and fundamental frequency are mainly concentrated in the low−frequency band (accounting for more than 99%), and the ratio of dominant frequency to fundamental frequency (T = dominant frequency/fundamental frequency) is stably maintained at 22−25 in different frequency bands. In the early stage, the T value fluctuates significantly, and in the middle and late stages, the T value tends to be stable, indicating that the crack propagation tends to be stable. Further analysis shows that there is a significant correlation between the dominant − to − fundamental frequency ratio and the amplitude ratio, which can quantitatively characterize the stage characteristics of crack propagation. This parameter provides a new quantitative index for revealing the mechanism of rock damage evolution and early warning of rock mass instability, and has important theoretical significance for monitoring the stability of engineering rock masses in mining processes.