In this study the recovery of alpha-glucosidase inhibitor from fermentation broth by Bacillus subtilis M1 for producing alpha-glucosidase inhibitory preparation was investigated. The effects of cultivation medium and recovery methods like ethanol precipitation, concentration condition, drying method on aglucosidase inhibitory activity after each step in recovery process were studied. Whereas the cultivation medium, concentration condition or drying method did impact on the activity strongly, the ethanol precipitation has only modest effect on that. Under standard pressure, higher concentration temperature resulted on higher loss of aglucosidase inhibitory activity. The concentration process under 100 mbar at 40°C for 80 min or at 50°C for 45 min reduced the alpha-glucosidase inhibitory activities insignificant. The a-glucosidase inhibitory preparation obtaining from 5 percent black bean medium fermented by Bacillus subtilis M1 and consequently recovered by ethanol precipitation, concentrated under 100 mbar at 50°C and freeze dried showed the alpha-glucosidase inhibitory activity with lowest IC50 of 0.0124 mg/ml.