In order to meet the demand of electrical equipment for high-performance power transformer, this paper studies inrush current phenomenon existing in high-power transformer and establishes the simulation model. The transformer inrush current phenomena is analyzed and mathematical modeling is done by using a new wavelet algorithm, the generating mechanism of three-phase transformer magnetizing inrush current and signal extraction method are studied, and the accurate fault recognition model is established. Finally, the simulation system is designed through Matlab/Simulink to achieve the recognition of three-phase transformer magnetizing inrush current waveform. Simulation results show that the simulation model can extract the relevant characteristics of the transformer inrush current, which provides a theoretical support for improving the performance of the transformer.