Abstract: Response surface methodology was used for optimization of fermentation medium and conditions which were screened by Plackett Burman design for antibacterial agents production by Bacillus licheniformis SN2 and suppression of Staphylococcus aureus ATCC 6538 growth. Seven factors were chosen to be screened by Plackett Burman design, yeast extract, peptone, NaCl, pH, temperature, incubation period and culture volume. Among ingredients, high concentration of yeast extract had a positive effect on antibacterial peptide production. Alkaline pH and high temperature favored the growth of B. licheniformis SN2. The optimal response region of the significant factors was predicted by using a second order polynomial model fitted to the results obtained by applying the Box Behnken statistical design. In this experiment, near basal concentration of yeast extract (7.4 g L-1), low level of peptone (2 g L-1) and near basal concentration of NaCl (2.8 g L-1) was highly increase the suppression % to 1.3 fold. Moreover, the optimized condition accelerated the reaction by reducing 6 h in suppression process.