Abstract: In this study the active antagonistic components from Brevibacillus brevs HAB-5 strain were isolated and purified mainly through low-temperature ethanol precipitation and Sephadex G-50 Gel column. The optimal fermentation medium ZS of HAB-5 was developed from LB to make HAB-5 produce the strongest antagonistic activity against Colletotrichum gloeosporioides Pen C7-2, and the optimal culture condition was incubation at 28 ℃ for 2 d with medium liquid volume in 50 mL/250 mL. Total bacterial proteins from HAB-5 did not show antagonism against the pathogen, but its supernatant exhibited strong antifungal effect. In the meantime, the medium block (MB), taken 1 cm from HAB-5 colony from ZS medium produced a significant inhibition zone against the pathogen. The HAB-5 supernatant treated by ammonium sulfate did not have antifungal activity, however, the crudes that were extracted from the supernatant or MB through low-temperature ethanol precipitation showed strong antifungal effect against the pathogen. Furthermore, the SDS-PAGE analysis of the crudes purified with Sephadex G-50 gel column showed a single electrophoresis band at 14.4 kD. Therefore, our results indicate that the primary antagonistic activity of peptides and the peptide with 14.4 kD may play an important role in it.