Abstract: To solve heating and warming problem on large and middle-scale biogas plants，taking a pig farm wastewater disposal biogas plant as an example, the economic benefits of three heating methods (biogas boiler, solar energy and biogas power generation waste heat utilization) were analyzed in this article. The results showed that ratio of investment was 2:11.2:1 to biogas boiler, solar energy and biogas power generation waste heat utilization, the annual cost of biogas power generation waste heating utilization method was only solar energy and gas boiler heating method’s 60% and 12%. Whether economic benefit, technical performance, or adaptability, persistence, biogas power generation waste heat utilization method were better than solar heating and gas boiler heating. Based on the natural and economical situation, the scheme of biogas power generation waste heat utilization is suitable for most large and middle-scale biogas plants in China.