Abstract：The air switch is an important electrical equipment in the low voltage distribution network. However, due to its internal special structure, resulting in the power line communication signal to produce deep attenuation in some frequency bands. In order to study the attenuation law of the air switch on the communication signal, it is necessary to accurately establish the high frequency circuit model of the air switch. Based on the conversion relationship between scattering parameters, the impedance and the transmission parameters of the two-port network and the characteristics of the series-parallel resonant circuit to establish the air switch high-frequency circuit model. The feasibility of the high frequency equivalent circuit model of air switch is verified by the comparison between MATLAB simulation and actual measurement results. The high-frequency circuit model of the air switch can accurately indicate the impedance and transmission characteristics of the air switch. At the same time, the modeling method is simple and applicable, which provides a reference for low voltage electrical modeling.