Abstract: Ten strains of potassium-releasing bacteria were isolated from the tobacco rhizosphere soil. Four strains with an obvious transparent zone and high efficiency proliferation were selected to investigate their potassium-releasing capacity. The K⁺ mass concentration in the fermentation broth of the strain GJ07 is 54.5% higher than that of the blank control group. The strain GJ07 was identified as Bacillus megaterium by the identification of 16S rDNA analysis. The batch culture conditions of the strain GJ07 were optimized via adjusting carbon sources, nitrogen sources carbon-to-nitrogen mass ratio, temperature, pH values and loading liquid. It is found that sucrose is the best carbon source, peptone is the optimal nitrogen source, the optimal carbon-to-nitrogen mass ratio is 10:1, the best temperature and initial pH value are 35℃ and 7.00 respectively, and the optimal loading liquid is 25 mL.