Abstract: Aminotransferase is one kind of important enzymes for the enzymatic preparation of amino acid. In the paper, the condition of fermentation for aminotransferase is optimized by low sensitivity robustness design according to the stability of fermentation process. After experiments, the volume of air and velocity of agitation are the two main factors affecting the production of enzyme, while other factors such as bath, pH value and temperature do not affect the fermentation result. The optimium condition is: air 0.6 L·min^-1, agitation 500 r·min^-1, pH6.5, 35℃, C. S. L2%. The results of fermentation with aminotransferase are very stable.