Under pressure toward carbon emission reduction and air protection, China has accelerated energy restructuring by greatly improving the supply and consumption of natural gas in recent years. However, several issues with the sustainable development of the natural gas industry in China still need in-depth discussion. Therefore, based on the fundamental ideas of sustainable development, industrial development theories and features of the natural gas industry, a sustainable development theory is proposed in this thesis. The theory consists of five parts: resource, market, enterprise, technology and policy. The five parts, which unite for mutual connection and promotion, push the gas industry's development forward together. Furthermore, based on the theoretical structure, the Natural Gas Industry Sustainability Index in China is established and evaluated via the Principal Component Analysis (PCA) method. Finally, a conclusion is reached: that the sustainability of the natural gas industry in China kept rising from 2008 to 2013, mainly benefiting from increasing supply and demand, the enhancement of enterprise profits, technological innovation, policy support and the optimization and reformation of the gas market.