Germany took a leading role in developing its biogas industry among European Union members and German Renewable Energy Sources Act was crucial for its renewable energy development. Ever since the enforcement of the code in 2000, it underwent four adjustments in line with the effect of implementation and problems encountered. Our study initially introduced the enactment background, the core content of the code and specific items in biogas sector. The impact on German biogas industry resulted from four adjustments of the law since 2004 was then quantitatively analyzed. With the transition of developmental background, the number and total capacity of newly installed biogas plants, along with cultivation area of energy crop and basic feed-in tariffs, were compared and the reasons for the variation were illustrated. The complete developing course of German biogas industry over 15 years with Renewable Energy Sources Act in force was also reviewed in this study. The analysis result indicated that German biogas industry had been significantly influenced by the code in that EEG-2004 and EEG-2009 stimulated its rapid development by granting substantial bonuses, while EEG-2012 and EEG-2014 corrected its excessive expanding, encouraging the power of renewable energy to compete with that of other sources in the market. In light of the impact by the Renewable Energy Sources Act, inspirations and lessons from German case on how China should develop its biogas industry were also discussed, including terminal subsidy.