Abstract: This article introduces the structure and fermentation technology of the double water pressure biogas digesters(BHZJ) made of glass fiber reinforced plastic.Comparing to conventional digesters,results indicated that the biogas generating rate of BHZJ biogas digesters was 0.381 m3·m-3·d-1 in daily average per volume and the daily average gas production was 2.30 m3,which increased by 27.0% and 27.8%,respectively.To evaluate the benefit in use of the biogas digester,the data showed that the annual energy benefits of biogas production in coal-equivalent and firewood-equivalent was 2.613 t·a-1 and 2.51 t·a-1,respectively,which reduced the cost for energy consumption in daily life by 1 251.6 Yuan·a-1.The emission of CO2 reduced by using biogas substitute for energy.The reducing amount of CO2 emission in substitute for coal and firewood was by 3.608 8 t·a-1 and 3.585 4 t·a-1,respectively.