Abstract: With the growing interdependence of power and natural gas (NG) systems, it is essential to perform a comprehensive and integrative analysis of the electricity-gas coupled system. Consequently, a dynamic modeling method for an NG network based on circuit analogy was proposed. The dynamic model of the NG network was constructed in power system simulation software. Firstly, the partial differential equations (PDEs) that described the dynamics of the gas pipeline were converted to ordinary differential equations (ODEs) based on the difference approximation. Through the analogy of the pneumatic quantity to the electrical quantity, an equivalent circuit model of the NG pipeline was constructed, in which the time-varying fluid resistance and incorporates constant impedance parameter were taken into account. Based on the regulator valve's pressure and throttling features, a constant impedance equivalent circuit model was set up and used to simulate its pipeline regulation characteristics. An electricity-gas coupled system was established, employing a single-shaft gas turbine as the energy conversion component. Subsequently, an in-depth analysis was conducted regarding the dynamic interaction impacts between the natural gas network and the power system. The simulation results demonstrate that the equivalent circuit model proposed in this paper exhibits high accuracy, and the model with constant impedance parameters can effectively enhance the simulation efficiency. Load fluctuations or valve malfunctions in the NG network can cause gas turbine output power instability and further affect the power grid, while gas turbine power modifications also influence the NG network flow and pressure distributions.