Abstract: Abstract: The strain Bacillus amyloliquefaciens BJ-6 can secrete antagonistic substances during the fermentation process, which can inhibit many different kinds of plant pathogenic fungi. In order to improve the yield of antagonistic substances, 18 different kinds of fermentation medium for Bacillus sp. were tested and 7 medium which suitable to ferment the Bacillus amyloliquefaciens BJ-6 have been selected out by shaking culture. On this basis, the strain was cultured by No. 2 medium in 5L fermentor. Biochemical methods were used to detect alive bacteria count, protein produced amounts, consumption amounts of carbon and nitrogen source. It showed that the best fermentation time is 96h and the best supplementary time of carbon and nitrogen source is 8h-12h. During the fermentation process, pH and dissolved oxygen concentration have been recorded automatically by fermentor.