Abstract: Five compounds were isolated from the petroleum ether extract of Dictamnus dasycarpus using various chromatographic techniques, such as column chromatography over silica gel and Sephadex LH-20. Their structures were elucidated by spectroscopic data(IR, MS, NMR), which were identified as docosanol( 1 ), ethyl 2, 2-dibenzhydryl-3, 3-di-phenylpropionate( 2 ), limonin( 3 ), obacunone( 4 )and dictamnine( 5 ). Compound 2 was a new compound and compound 1 was isolated from this plant for the first time. PNPG method was used to determine α-glucosidase inhibitory activity of these compounds. The results indicated that compounds 3 - 5 possessed stronger inhibitory activities than the positive control of acarbose, which provided a theoretical basis for further development and utilization of Dictamnus dasycarpus.