Abstract: The vibration acceleration signal of the cutting reducer under different working conditions of roadheader was collected and analyzed in the time domain, frequency domain and time-frequency domain. In time-frequency domain, some intrinsic mode functions were obtained using variational mode decomposition, each component signal was demodulated by Teager energy operator, and the variation of instantaneous frequency was analyzed. The frequencies of 280Hz and 350Hz appeared repeatedly, which is related to the working frequency of the roadheader. The conclusions provide data support for studying the vibration characteristics of the roadheader, optimizing the structure design, monitoring the real time state and carrying on the fault diagnosis.