Abstract: Under the guidance of inhibition α-glucosidase activity in vitro, the inhibition effect and mechanism of inhibiting α-glucosidase activity of different polar components obtained from Sparassis crispa were investigated. The extracts of S. crispa were obtained by the ultrasonic-assisted extraction methods with two different ethanol concentrations. The different polar components were obtained by the extraction and the macroporous adsorption resin. All of these fractions were screened by the α-glucosidase inhibitory activity in vitro, and the active fractions were obtained. Half maximal inhibitory concentration(IC₅₀) was calculated, and the mechanism of action was investigated by enzymatic kinetics and Lineweaver-Burk methods. The results showed that the inhibition of α-glucosidase activity was strongest in the 60% ethanol eluting fraction of the extract of 50% ethanol, with IC₅₀ value of 0.0927±0.0600 mg/mL, which was equivalent to the activity of acarbose(IC₅₀: 0.0795±0.0200 mg/mL). It was competitive and non-competitive mixed inhibition type. This study identified the avtivity fraction of inhibiting α-glucosidase in the extract of S. crispa, and discussed the mechanism of action. It would provide a theoretical and scientific basis for developing hypoglycemic products for S. crispa in the future.