The high construction cost of biogas project on China’s breeding farms and the low direct economic effect severely impede the commercialization of concentrated biogas supply. At present, there are no feasible subsidy policies such as subsidy for raw materials and end product or tax reduction despite the fact that subsidy is the effective way for biogas project investment and operation. A number of Chinese scholars study the successful experience of German biogas product subsidy which can improve profit, and propose changing the existing subsidy method and adding the subsidy content. Yet there are few researches focusing on calculating the price subsidy standard for biogas project end product. Some scholars propose the subsidy from the perspective of external effectiveness of biogas projects, which is however infeasible because of the difficulty of quantifying social and environmental effect of applying biogas projects. By the method of cost pricing, this article analyzes construction cost, operation cost, and opportunity cost of biogas projects of various sizes. The advantage of this analysis is the convenience of collecting cost data and the feasibility. When the biogas project supplies for 100 households, per capita investment is 17900 yuan/household, and when the biogas project supplies for 1 500 households, per capita investment reaches 4 100 yuan/household. According to the U-shaped curve of average cost, when supplying for more than 800 households, the concentrated biogas supply project is the optimum. This indicates that the concentrated biogas supply projects comply with the rule that the cost decreases when the project size goes up. By analyzing biogas supply cost, it is found that the change range falls into 3 different stages. When supplying for less than 200 households, the cost decreases at a sharp rate with the expansion of size. When supplying for 200-800 households, the cost goes down at a slower rate. And when supplying for more than 800 households, especially 1 000 households, the biogas supply cost curve approaches a line, demonstrating that it reaches the optimum point of biogas supply size. Thus, a subsidy price is calculated based on supply cost: subsidy price is 4.73 yuan/m3 when supplying for 100 households; 2.98 yuan/m3 for 200 households; 1.63 yuan/m3 for 800 households; 1.51 yuan/m3for 1000 households; and 1.42 yuan/m3for 1 500 households. By this way, this article estimates the supply cost of biogas projects with various supply scales, and calculates a subsidy criterion for biogas projects with varied biogas supply scales on breeding farms. Small supply capacity requires high subsidy cost, whereas large supply capacity requires low subsidy. Consequently, a subsidy criterion is put forward and a subsidy method is suggested: A combination of enhancing the government subsidy before the project and the subsidy for the users. This subsidy criterion provides the advice for the government, which is beneficial to motivating enterprises to establish the profit earning model of concentrated supply of biogas project and improving the commercial and sustainable operation of concentrated biogas supply projects. Therefore, it has important meaning for the appropriate upgrading of biogas projects of breeding farms.%中国养殖场沼气工程建设成本高、直接经济效益低等问题严重阻碍了沼气集中供气商业化发展。该文采用成本定价法，通过对不同供气规模养殖场沼气工程的建设成本、运营成本以及投资机会成本进行分析，集中供气工程建设规模为100户时，户均投资达到1.79万元/户，当供气户数规模提升到1500户时，户均投资仅为0.41万元/户，根据平均成本U型曲线，供气户数达到800户以上后，沼气集中供气工程规模逐渐接近于沼气工程最优规模点。按照供气成本计算出供气100户，补贴价格为4.73元/m3；供气200户，补贴价格为2.98元/m3；供气800户，补贴价格为1.63元/m3；供气1000户，补贴价格为1.51元/m3；供气1500户，补贴价格为1.42元/m3。分析出不同规模养殖场沼气集中供气工程，供气规模小，补贴成本就越高，供气规模大，补贴就越低，集中供气工程供气达到1000户以上规模时，基本接近于最优供气规模点，补贴价格趋于平衡能实现盈利。建议政府应加大力度建设前端补助与终端用气补贴相结合补贴方式，并提出集中供气补贴标准。
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