In order to explore the inhibitory effects of immature persimmon extract on human salivary α-amylase (HSA)， porcine pancreatic α-amylase (PPA)， α-glucosidase (α-Glu) and changes in postprandial blood glucose immature persimmon extract on mouse， the immature persimmon extracts was prepared by ultrasound-assisted acetone extraction and macroporous resins purification using immature persimmon as raw material. The in vitro enzyme inhibition effect and mechanism of action of immature persimmon extract were analyzed by enzyme activity inhibition rate， enzyme kinetics and enzyme fluorescence quenching assay， and finally the control effect of immature persimmon extract on postprandial blood glucose level was verified by animal test. The results showed that immature persimmon extracts inhibited the activities of HSA， PPA and α-Glu， and the types of inhibition were all mixed， with half-inhibitory concentration values (IC50) of (16.18±0.17)， (13.57±0.30) μg/mL and (3.22±0.03) μg/mL， respectively. There was all one binding site between the three enzymes and the extracts， indicating that the interaction of immature persimmon extract with the fluorescent chromophores of HSA， PPA and α-Glu spontaneously forms a complex that causes alteration of the microenvironment around the chromophores of HSA， PPA and α-Glu and quenching of the endogenous fluorescence of the enzymes， thus the enzymatic activity was inhibited. Animal experiments revealed that immature persimmon extract significantly reduced postprandial blood glucose levels in mice indicated immature persimmon extract could reduce postprandial blood glucose level by inhibiting HSA， PPA and α-Glu activities.