Larger-leaf yellow tea (LYT) is a characteristic type of Chinese tea produced in Huoshan County, Anhui Province, which is made by mature leaves with stems. According to recent report, LYT showed competitive effects in anti-hyperglycemia in comparison to other teas such as green or black tea. However, the?bioactive compounds?of LYT are still undiscovered so far. For this purpose, 5 fractions of LYT were prepared by sequential extraction. The?in vitro?bioassay results indicated that the?ethyl acetate?fraction of LYT had the strongest inhibitory effects on?α-glucosidase and?α-amylase. Fluorescence-quenching analysis and protein-binding test revealed that the compounds of ethyl acetate fraction could inhibit?α-glucosidase and?α-amylase activities through binding to enzymes or other mechanisms. All chromatographic peaks of high-performance liquid chromatography (HPLC) of ethyl acetate fraction were separated and collected. The purified compounds were identified by liquid chromatography-mass spectrometry (LC-MS), and subsequently screened by calculating their inhibition ratio on?α-glucosidase at the real concentration in LYT infusion. The results showed that (–)-epigallocatechin?gallate, (–)-gallocatechin gallate, caffeine,?N-ethyl-2-pyrrolidone-substituted flavan-3-ols were effective inhibitors for?α-glucosidase.