Abstract: Chaetomium cupreum CH-1 was fermented in liquid culture. To keep the activity of the antifungal compounds during the processing, we studied the physical and chemical properties of the broth using Colletotrichum capsici as bioassay indicator. It indicated that the broth would keep activities while the temperature within 60 ℃ and the pH values from 3 to 5, and the active compounds would be extracted effectively with the ethyl acetate. Purification of the active compound in the broth of the strain was performed using a combination of extraction, flash column chromatography, crystallization and re-crystallization. The active compound named oosporein was elucidated by UV-Vis, IR, HR-ESI-MS and NMR spectra and had a broad application prospect in prevention and control of plant pathogenic fungi.