Abstract: For problem that partial discharge signal of electrical equipment is easy to be overwhelmed by narrowband interference signal in field operation environment, and is difficult to extract, a new method of narrowband interference suppression of partial discharge signal based on sparse decomposition resonance was proposed. Quality factor, redundancy factor, decomposition level and the weight coefficients were analyzed and selected, sparse decomposition of partial discharges signal with narrowband interference was realized according to the oscillation characteristics of partial discharge signals and narrowband signal. The partial discharges signal with narrowband interference was decomposed into high resonance component, low resonance component and residual component, so as to extract effective partial discharge signal. The method can effectively suppress narrowband interference, and has small error and high similarity compared with wavelet transform threshold filtering method. The results of simulation and experimental data demonstrate the effectiveness of the method.