The interface polarization model for double-layered nonlinear dielectrics is established based on nonlinear dielectrics with a+bE-type nonlinear conductivity (that is, the conductivity of dielectrics is a linear function of the electric field). The dynamic characteristics of the electric field, the interface charge, and the current during polarization and depolarization have been deduced analytically. The theoretical research results show that the electric, the interface charge, and the current have three kinds of models during the polarization: the exponential model, the hyperbolic tangent model, and the hyperbolic cotangent model. However, only the hyperbolic cotangent model occurs during the depolarization. The total current during polarization includes the DC steady state current and two absorption currents with different half-value period, and depolarization current contains two components with different half-value period. Because of the different polarities and values of two components, the depolarization current presents a variety of forms. Through theoretical derivation of the interface polarization of double-layered nonlinear dielectrics with a+bE-type nonlinear conductivity, the nonlinear interface polarization dynamic behavior is theoretically expounded and a foundation for future research into more complex nonlinear interface polarization is laid.