Based on the super-long term forecast, by analyzing the supply and demand situation of oil & gas for our country in 2030—2050, some strategic measures and advice on energy security challenge were put forward. The results showed that in a long period, our national demand for petroleum will be at strong growth, but the petroleum production will keep stable. Therefore, the gap between supply and demand is constantly increasing. In order to confine the dependency of domestic petroleum consumption on import at 60 %, it is necessary to control energy demand and develop reliable petroleum substitution at the same time. As a clean and fine fossil fuel, natural gas is of great significance to change our national energy structure and promote a low-carbon economy, so it is urgent to take effective measures to quicken domestic natural gas exploration and import as much natural gas resource as possible from oversea market, and to realize the goal that the proportion of natural gas can reach more than 10 % in our national primary energy structure in 2030—2050. According to the results, the sustainable strategy and technical options for oil & gas mid-long term development in our country were also proposed, and suggestions on strategic measures were given.