Abstract: The test of anaerobic digestion with mixed material of lipid-extracted residue of Tribonema minus and cow dung was carried out. The results showed that the mixed anaerobic digestion system could keep the fermented liquid at a suitable pH value for the growth of the methanogens. While the ratio of lipid-extracted residue of Tribonema minus and cow dung was 4∶6, there were the highest cumulative gas production （783 mL）, unit CH₄ production rate （9.8 mL/（d·g VS））, higher daily gas production（86 mL/d）, cumulative CH₄ production （88.07 mL/g VS）, and the shortest fermentation detention time （2.1 d）.

Key words: Tribonema minus, lipid-extracted residue, cow dung, co-anaerobic digestion