Subsynchronous oscillation is a kind of abnormal electromagnetic and mechanical oscillation which occurs when the equilibrium point of power system is disturbed. Aiming at the problems of noise interference and mode aliasing in the extraction of subsynchronous oscillation components by the Hilbert Huang transform, a method combining multisynchrosqueezing transform (MSST) and Hilbert transform is proposed to identify subsynchronous oscillation parameters. Based on Fourier synchronous compression transform, the frequency spectrum of subsynchronous oscillating signal is compressed synchronously for several times, so as to improve the reconstruction accuracy of signal timefrequency distribution and the degree of energy aggregation. Through simulation and verification combined with actual engineering recording data, firstly, the signal timefrequency analysis was carried out using the multisynchronous compression transform method to obtain the signal timefrequency diagram, and then the multisynchronous compression transform transform inverse transformation decomposition was used to reconstruct each modal component, and finally the extracted single modal component parameter identification was carried out using the Hilbert transform. Identify its frequency, damping ratio, attenuation factor and other major parameters. The simulation results show that compared with shorttime Fourier transform (STFT) and synchroextracting transform(SET) and Fourierbased synchrosqueezing transform (FSST). MSST can improve the energy concentration degree and reconstruction accuracy of signal timefrequency distribution, and realize multicomponent subsynchronous oscillation mode decomposition. The actual data show that the method can overcome the noise interference and mode aliasing effectively, identify the subsynchronous oscillation parameters accurately, and has certain reference significance for the safe and stable operation of power system.