Abstract: An Aspergillus oryzae and its application belong to the field of microbiology and food processing technology. The present application, on the one hand, provides an Aspergillus oryzae (WZ-212), on the other hand, provides this Aspergillus oryzae in application of enhancing the inhibitory activity of ?-glucosidase by grapefruit peel and the method of application. Using the Aspergillus oryzae of this application to treat grapefruit peel, the inhibition of ?-glucosidase activity by grapefruit peel extract was significantly enhanced, and the process is simple, low cost, which is easy to achieve industrial production.