As an important part of urban infrastructure, the city gas network is an important indicator of the city's energy supply capacity and modernisation level, but with the increasing complexity of the underground gas network system, the traditional gas operation and maintenance management has been difficult to meet today's needs. Digital twin technology has the characteristics of real-time synchronisation, faithful mapping and high fidelity, which can realise the interactive integration of the physical world and the information world. The design ideas and principles of the city gas digital twin system were put forward , and a management platform for practice was built , which proves the significant advantages and application value of the digital twin technology in the construction and management of gas pipeline network.