Abstract: The benefit from household digester utilization, especially the beneficial effect of the comprehensive utilization of fermentative residue to agricultural economic development has attracted more and more attention day by day. The problem of how to quantatively evaluate the benefit from biogas technology utilization has been raised. On the basis of investigation to over 1000 farm households who use the biogas digesters and statistic analysis by means of SPSS-Software Package of Social Statistics, this paper describes the present situation of family-size digesters, the direct benefit from the comprehensive utilization of fermentative residue and its effect to farm households' economic income. It can supply a good reference for policy-making in household digesters' development.The analysis shows that the family-size digester technology is well received by an overwhelming majority of farmers , especially the ordinary households; the aim of building digester is diversified, not only energy, comprehensive utilization , but also environmental sanitation and public health have been taken into consideration; the benefit from household digesters' utilization is not simply showing in energy supply, but the comprehensive utilization benefit of fermentative residue is more important. The economic analysis shows that the internal return ratio is 4. 5% if only the biogas benefit is considered, while the ratio accounts for 21.6% if the substitute benefit of biogas fertilizer for chemical fertilizer, pastcides and feed is considered: furthermore if thinking of the total benefit of biogas and fermentative residue utilization, the internal return ratio could rech as high as 74. 9%. Therefore, the high total benefit of biogas as fuel and fementative residue as fertilizer leads to a favorable receiving of biogas technology.This paper also analyses how the comprehensive utilization of biogas fertilizer affects family income by method of correlation and regression analysis. According to the contribution to economic income, the uses of biogas fertilizer are listed in the following sequence; aquaculture, vegetable planting and returning to farm field.