Abstract: Mitigating energy tension,reducing CO2 emissions of greenhouse gases isthe main purpose of developing new energy.According to"Reduce,Reuse,Recycle"as the guide,In the early course of study,the task of Fuel ethanol project is optimizing the production process of cassava fuel ethanolin whole life cycle,reducing the use of external carbon source,reusingthe wastefrom planting to the production process,making full use of carbonin cassava raw material,and realizing the carbon closed loopduring production process.Replaced the fossil energy of the original production process by recycling of waste,we can reduce the CO2 emission.