The calculation and evaluation of energy conservation and emissions reduction benefits of the rural household biogas project and its up stream and down stream sectors can provide decision making basis for whole process environmental management of the rural household biogas project and rural renewable energy development. In this paper, life cycle assessment method was established with inventory of a typical 8 m3 rural household biogas project and then the net energy conservation and emission reduction benefits were calculated and evaluated. The results showed that the life cycle reduction potentials of eutrophication, acidification, energy depletion, greenhouse effect, human toxicity and photochemical oxidation impacts of a typical 8 m3 household biogas project accounted for 84.84%, 54.37%, 39.16%, 27.67%, 19.35% and 5.55% of the relevant environmental impact potential per capita in the world in 2000, showing a significant net energy conservation and emissions reduction benefits. Therefore, the development of rural household biogas project plays a significant role in alleviating the fossil energy shortage situation and controlling the agricultural non-point source pollution in rural areas.