Abstract: The key technologies and their implementation methods of RealPipe-Gas simulation software for gas pipelines are discussed. The simulation engine can describe and explain the gas pipeline network with arbitrary topological structure effectively. Linearizing the created system of nonlinear equations and discretizing the system of linear equations in time and space are carried out, and then a large-scale sparse coefficient matrix is formed. An efficient solver has been developed to solve the model and "Leapfrog" strategy is used to solve hydraulic system and thermal system. Through these methods, the computational efficiency and stability are greatly improved. By comparing and analyzing the computational results by RealPipe-Gas1. 0 and SPS (Stoner Pipeline Simulator), it is concluded that the computational accuracy, efficiency and stability of RealPipe-Gas1. 0 have reached the advanced level of some international commercial simulation softwares. The research will lay the groundwork for the localization of oil and gas pipeline simulation software.