Abstract: The coupling relationship between natural gas networks and power systems is increasingly tight. This paper first analysed two systems with precise mathematical models to model the key components, and simplifies the non-critical components. In the modeling process, restrictions of node pressure, gas well output, pipeline transmission, etc. of the natural gas network were taken into account. Based on the IEEE24-node power system and the Belgian 20-node natural gas network for gas-electric coupling joint operation simulation, an economical optimal scheme for gas-electricity combined operation considering natural gas transmission characteristics was obtained. On the basis of this, then the line overload of the power system was studied. Due to its high ramp rate, the gas turbine output can be quickly adjusted to eliminate the overload of the line, and the user’s power consumption is not affected. Based on the gas-electricity coupling model, the optimization scheme was compared from the aspects of rapidity and economy. It is concluded that the insufficient gas quantity will affect the ramp rate of the gas turbine. If it is considered to solve the line overload problem at the fastest speed, it must sacrifice certain economic costs.