Abstract: The coupling of electricity and natural gas systems is increasingly close,and the mutual influence is more and more intense.The failure of natural gas system affects the fuel supply to gas units and the stable operation of the power system.The determination of access points of gas turbines in natural gas systems plays an important role in securing their fuel supply.The gas flow calculation of the natural gas system is modeled,and N-1 static safety analysis predication accident set of pipeline is set up.The gas flow of natural gas system before and after breaking is simulated with the goal of minimizing the operating cost of natural gas system. Quantitative evaluation indexes of accident after the break-down of the natural gas N-1 pipeline branch are established to evaluate key branches and important nodes.By ranking the evaluation indicators,the key pipeline branches and important nodes of the natural gas system are determined,the gas turbine access planning strategy is proposed,and the access point of the gas turbine in the natural gas system is determined.The established planning strategy can provide a complete set of scheme references for reliable access of gas units in the power system to the natural gas system.