Wavelet technology is used to analyze the voltage waveform characteristics of every winding subsection under the respective mode of single-point partial discharge (PD) and double-point PD, and to compute the function value of wavelet energy of fault signal after reconstruction. The results indicate that the function value obtained by wavelet analysis can well distill the characteristics of fault signals in coil, which may provide a guidance for PD pattern recognition and fault location of transformer winding.