For non-linear characteristics of power quality disturbance signal, the characteristic parameters of power quality disturbance signal such as amplitude, frequency, phase, attenuation factor and the starting and ending time of the disturbance can be quickly and accurately extracted by intrinsic time-scale decomposition. Firstly, voltage disturbance signals are decomposed into proper rotation component (PRC) by intrinsic time-scale decomposition algorithm. To apply the Hilbert transform to get phase and instantaneous frequency of PRC components, then according to hyper mutation of instantaneous frequency, the starting and ending time of the disturbance are got; the envelope function is utilized to calculate amplitude and the attenuation factor. Utilizing Matlab, simulations of single disturbance signal and mixed disturbance signals are done and calculation results show that this method can accurately identify power quality disturbance signal parameters and anti-noise performance. The timeliness and feasibility of the proposed method is verified.