Gentamycin was applied inclusively,its pharmacodynamic was stable,and its fermentation process was mature and production scale was large in our country. In pace with promulgating and implementing of new pharmacopoeia, the more stringent requirements were carried out of gentamycin production. The improved fermentation techniques were studied in a 30 L bioreactor. Different CoCl2 condition in fermentation medium, ventilator capcity and inoculums size were researched in this examination,and the optimum fermentation formulation: 2 μg/mL CoCl2 in fermentation medium, inoculums size was 10% ventilator capcity was 1∶1. Finally, the fermentation level was further improved by 13.5% in average. If the results was enlarged and used in the production, the production level and efficiency of gentamycin would be improved significantly. Beside that the components and impurity contents accorded with the new pharmacopoeia request.