The UPLC chromatographic column was acquity ACQUITY UPLC BEHC₁₈ (50 mm×2.1 mm,1.7 μm),with 0.2% acetic acid-acetonitrile as the mobile phases in gradient solvent system.The detection wavelength was set at 250 nm with flow rate of 0.3 mL/min,and phytoecdysones components were determined in the chromatographic conditions.Then the antioxidant biological activity was reflected through ABTS radical scavenging rate,DPPH radical scavenging rate and hydroxyl radical scavenging rate.Finally,a two-classification logistic regression model was based on correlating biological activity and components.All 21 batches of Achyranthes bidentata were divided into four grades according to this model.The results showed that it was feasible to describe the mapping relationship between the grade and the influencing factors by this model,which could provide a new idea for the evaluation standard of A. bidentata.