The scale-up strategy for acarbose fermentation by Actinoplanes sp.A-56 was explored in this paper.The results obtained in shake-flask cultivation demonstrated that the ratio of maltose and glucose had significant effect on acarbose biosynthesis,and the feeding medium containing 3∶ 1(mass ratio) of maltose and glucose was favorable for acarbose production.Then the correlation of carbon source concentration with acarbose production was further investigated in 100 L fermenter,and the results showed that 75~80 g/L of total sugar and 40~45 g/L of reducing sugar were the optimal for acarbose production.Based on the results in 100 L fermenter,an effective and simplified scale-up strategy was successfully established for acarbose fermentation in a 30 m3 fermenter by using total sugar and reducing sugar as the scale-up parameter.As a result,4 327 mg/L of acarbose was obtained at 168h of fermentation.