Abstract: The mixed transportation of hydrogen through natural gas pipeline transportation system can realize large-scale, low-cost and long-distance transportation of hydrogen. However, mixed transportation of hydrogen brings more severe safety and technical challenges. This paper discusses the safety of long-distance pipeline transportation of hydrogen-doped natural gas around several key technologies, such as transportation technology and key equipment, pipe compatibility and life prediction, leakage monitoring and risk assessment, and standard system construction. It is suggested to plan the transportation network as a whole, improve key pipeline transportation processes and equipment, establish a big data platform for transportation coordination emergency and intelligent decision-making, formulate specifications and standards for hydrogen-doped natural gas pipeline transportation, and gradually carry out application demonstration of hydrogen-doped natural gas transportation technology.