Abstract: The effects of fermentation duration and temperature,bacterium age,inoculum amount,rotating speed of bottle shaking and dissolved oxygen quantity on bacterium amount,and the relationship between fermentation conditions and the amount of Xiang 2-3,a strain against Ralstonia solanacearum,were studied,and the optimum fermentation conditions were determined by orthogonal test.The results indicated that the optimum fermentation conditions for Xiang 2-3 were:fermenting for 24h at 28℃,bacterium age 18h to 22h,inoculum amount 4%,rotating speed 210r/min,and dissolved oxygen 100mL/150 mL.