1. Nitrogen fixation by Dematium pullulance is studied, using glucose as the carbon source. 2. Nitrogen fixed per lg of glucose reached 1400mg. So that this fungus has the highest power of nitrogen fixation ever known. It is about 100 times of that of Azotobacter. 3. The velocity of nitrogen fixation is very great. 4. The smaller the concentration of glucose in the medium (in the range of 0.2_??_2%), the greater is the nitrogen fixation.