Phyllanthi Fructus (PF) is a tropical fruit with the potential to effectively reduce postprandial blood glucose. However, the lack of quantitative evaluation methods and comprehensive understanding of hypoglycemic active compounds has hindered the development and application of functional foods and dietary supplements derived from PF. In this study, based on the "mass reaction parallel line method", with acarbose as the control and PF extract as the test material, a biological evaluation method for PF hypoglycemic activity based on α-glucosidase inhibition was established for the first time. The in vitro and in vivo validation experiments showed that the coefficient (r) of correlation between the biological evaluation results and the AUC of rat postprandial blood glucose concentration was as high as 0.866, which confirmed the reliability of the evaluation method. The analysis of 20 batches of PF samples showed that the hypoglycemia potency of PF ranged from 2.66 to 8.39 U mg-1, with an average value of 4.00 U mg-1, and the standard deviation was 1.5. UF-LC-MS was used to identify 36 components of PF capable of binding to α-glucosidase. Molecular docking results showed that the binding energy was between -3.5 and -14.3 kJ mol-1. The hypoglycemic activity of 17 available control products was tested, and 8 inhibitors were found, including hyperoside, gallic acid, and corilagin. Dose-effect analysis suggested that flavonoids and polyphenols with a phenolic hydroxyl structure could inhibit α-glucosidase. In short, this study provides a basis for the development of PF hypoglycemic functional foods.