Predicting the emission reduction costs and potential of sustainable aviation fuels that are in line with China"s national conditions is crucial for promoting the development of the SAF industry and achieving carbon neutrality goals. Based on the principles of international comparability and independent controllability, a full lifecycle carbon reduction model for HEFA and G+FT technology paths was constructed, and the emission reduction amount and cost of China"s civil aviation SAF from 2025 to 2060 were predicted. Research has found that the HEFA route using waste oil as raw material and the FT route using agricultural waste, forestry waste, and urban solid waste as raw materials reduce carbon emissions, emission reduction costs, and emission reduction contributions by 61.3, 66.4, 65.9, and 68.4 kg [CO] 2e/GJ, 84.4%, 91.3%, 90.7%, 94.2%, 0-1025.9, 2307.2-4536.1, 488.6-2179.4, 327-1566.1 CNY/ton [CO] 2e, respectively, compared to traditional aviation kerosene. It is expected that the SAF emissions reduction of China"s civil aviation industry will be approximately 171.77 million tons to 198.19 million tons by 2060. From 2025 to 2060, the cumulative carbon reduction costs under possible scenarios will reach 1106.3-4582.8 billion yuan, with marginal carbon reduction costs ranging from 220-697CNY/ton.