The current and inductance of transformer under the AC-DC hybrid condition have significant differences from the traditional cases. An identification method is put forward through the electromagnetic mechanism in this paper. The field-circuit coupling model of transformer is established, which is decomposed into inductance calculation and current computation, as the key parameters to realize the coupling. By solving the magnetic field with the edge finite element method, the energy of systems is calculated using the local linearization method. And the inductance is computed based on the energy principle. Meanwhile, the time-domain electrical circuit model is calculated by the fourth order Runge-Kutta method. The electromagnetic characteristics of transformer are learned considering different conditions. The fluctuations of dynamic inductance is analyzed and summarized by combining with the saturated states of excitation. Comparing the computed results with the experimental data shows consistency. And the method proposed is proved.