The inhibitory effects of aloe extracts on α-glucosidase activity were investigated. The aloe with the best inhibitory effects on α-glucosidase was screened from 5 species, in order to obtain the functional composition of reducing the postprandial blood glucose. The best variety of aloe was determined according to the inhibition rate by α-glucosidase inhibitor screen model in vitro; and the type of enzyme inhibition was decided by enzyme concentration-response speed and L-B graphing method. Results showed that the ethanol extract of aloe arborescens miller showing the best effects had the highest inhibition rate of 87.95%; aloe extract was noncompetitive inhibitor of α-glucosidase and showed dose-dependent relationship. The Km value of aloe extract was 0.442 mmol/L. The enzyme inhibition kinetics process curve showed the time of initial velocity of reaction was 18 min. It suggested that aloe contained α-glucosidase inhibitors with high effects, and could be developed for the treatment and prevention of diabetes and its complications.