Abstract: A new method of location and classification of power quality disturbance based on wavelet packet and PNN was proposed according to essential characteristics of transient power quality disturbance. The disturbance signals were sampled and decomposed by using wavelet packet to extract wavelet packet reconstructed coefficient and to locate signal saltation point, then the energy of each band was calculated and normalized, energy feature vectors were constructed as input sample of PNN for network training and testing, and finally classification of different disturbance signal was achieved. Matlab simulation results show that the method can quickly and accurately locate and classify disturbance signal．