Abstract: In order to make full use of algae residue in the process of fermentation and oil production of heterotrophic Chlorella, the p H, NH₄⁺, COD, total carbon content, VFA content and gas production were used as the indexes and algae residue in the production process were used as a research object for biogas fermentation in this article.The results showed that the fermentation system of using raw material by thermal acid 1000 m L of fermentation broth 56 days of gas production was 7700 m L at 50 ℃fermentation temperature, the gas production was the highest.In this fermentation process, the p H was decreased, indicating that the acidification process is proceeding smoothly.NH₄⁺, COD, VFA content, total carbon content change range is small, indicating that the raw material utilization rate was relatively high, the fermentation process was relatively stable.The research provides a reference for the selection of oil extraction process from heterotrophic Chlorella and the use of waste during the process of oil production.