Transformer-inductor simulation model not only reflects the characteristics of magnetic path and circuit, but also brings in magnetic components that reflected the parasitic capacitance. There are further research, strict derivation and magnetic circuit equivalent for the model in this article. Under the condition of considering hysteresis, saturation effect we can conclude a new modeling and its equivalent, which can make the magnetic curve and characteristic get better fitting. It shows that the transformer-inductance simulation model is easy to spread and use.