The invention discloses a method for screening an alpha-
amylase inhibitor. The method comprises: preparing an enzymatic reaction
buffer solution, a substrate solution, an alpha-
amylase solution, a color-developing
reagent solution, and a to-be-tested product solution for later use; performing sample application of the to-be-tested product solution on a
thin layer plate; allowing a
solvent to be volatilized or using a proper developing
solvent for developing, performing air-
drying, and soaking the obtained product in the substrate solution; taking the obtained product out, allowing the
solvent to be volatilized, soaking the obtained product in the alpha-
amylase solution, and carrying out an enzymatic reaction at 5-50 DEG C for 10-60 min; after the reaction is completed, taking the obtained
thin layer plate out, allowing the solvent to be volatilized, soaking the obtained product in the color-developing
reagent solution for a color-developing reaction; and viewing the obtained
thin layer plate in visible light. Blue spots which appear in the white or yellow or brown background are the alpha-amylase inhibitor. The invention provides the method which enables the alpha-amylase inhibitor to be conveniently fast screened and provides an ideal approach for screening active ingredients containing the alpha-amylase inhibitor from natural substances.