Abstract: In view of the fact that traditional analysis method is hard to analyze the non-linear and non-stationary power grid signal, a method of extracting current phase based on Hilbert Huang transform (HHT) is proposed. In response to the ubiquitous mode mixing phenomenon of empirical modal decomposition (Empirical Mode Decomposition, EMD) during decomposition, this method decomposes the new current signal into a series of intrinsic mode functions(Intrinsic Mode Functions, IMF) through adding auxiliary signals based on the relevant parameters of the original current signal. If the mode mixing phenomenon is removed, the high-frequency signal will be filtered. If not, the new auxiliary signal will be iterated for analysis until the phenomenon is removed. The IMF component of the fundamental frequency signal with the mode mixing removed will be extracted, and the phase of the fundamental frequency signal can be obtained by Hilbert transform. Matlab is used to simulate the voltage sag, harmonic interference and other fault signals in the actual power grid, and the simulation results verify the effectiveness and accuracy of this method for phase extraction.