Abstract: Objective: The inhibitory effect of mogrosides crude extract on the activity of α- glucosidase was studied.Methods: The fluorescence spectroscopy methods and spectrophotometry were used for analysis the inhibitory activity of mogrosides crude extract on α- glucosidase.Results: The mogrosides crude extract had inhibitory effect on α- glucosidase with 9.125 mg / m L IC50 value. The kinetic and fluorescence spectroscopy analysis showed that the inhibition effect of mogrosides crude extract on α- glucosidase belonged to mixed inhibition,which had strong static quenching effect on the intrinsic fluorescence of α- glucosidase. Conclusion: The mogrosides crude extract had inhibitory effect on the α- glucosidase activity,which indicated that mogrosides crude had good application prospects in antidiabetic product development.