The current Russia-Ukraine war has elevated the issue of oil and gas security to a new strategic height. Accurately assessing the future supply and demand fornatural gas is of great strategic significance for the construction of major natural gas energy security projects. This paper innovatively divides natural gas consumption into three categories: survival, production, and non-bottom-line consumption.It predicts medium- and long-term natural gas consumption under conditions of multi-factor collaborative uncertainty and makes a comprehensive study and judgment of the natural gas supply and demand situation under the bottom-line thinking. The results show that, first, under the three scenarios of recoverable reserves, natural gas production will peak in 2030, 2033, and 2037, with peak productions of 2 441.46, 346.492 and 422.795 billion cubic meters, respectively.Second, by 2030, the lowest production consumption accounts for 31.70% of the bottom-line consumption, but its average annual growth rate far exceeds that of survival consumption.Third, the bottom-line consumption in 2025 and 2030 will reach 3 057.19~3 578.61 and 3 704.95~4 730.81 billion cubic meters, respectively. If the cascade gas consumption thinking is strictly implemented, subsistence consumption can basically achieve self-sufficiency under any production scenario.However,the lowest self-sufficiency rate for production and consumption under the most optimistic scenario of natural gas production at the end of the “15th Five-Year Plan” does not exceed 52%.Furthermore, even under ascenario of one times production and consumption, there may be complete dependence on external sources. Fourth, in the scenario of two times or 1.5 times natural gas production, the external dependence on natural gas can be strictly controlled within 50%; however, the effect of using different scenarios to reduce this external dependence is limited, with a maximum reduction of 8.71%. The research conclusions are of great significance for ensuring the balance between the supply and demand of natural gas in my country and implementing the energy security strategy.