Investigation on the Chemical Constituents in the Roots of Acanthopanax trifoliatus (Linn.) Merr., with methanol used for extraction, followed by sequential partitioning with petroleum ether and ethyl acetate to obtain the methanol extract, petroleum ether fraction, and ethyl acetate fraction. After evaluating the cytotoxicity of these fractions via the MTT assay, α-glucosidase inhibitory and antioxidant activities were screened, identifying the ethyl acetate fraction as the most bioactive component. Targeting this fraction, a combination of chromatographic techniques including macroporous resin chromatography, normal-phase and reversed-phase silica gel column chromatography, Sephadex LH-20 gel filtration, and semi-preparative high-performance liquid chromatography (HPLC) was employed for the isolation and purification of chemical constituents. The structures of the isolated compounds were elucidated by spectroscopic analysis combined with physicochemical properties. Additionally, molecular docking, α-glucosidase inhibitory assay, and DPPH/ABTS free radical scavenging assays were performed to evaluate the bioactivities of selected monomeric compounds. Fourteen compounds were isolated from the ethyl acetate fraction and identified as chlorogenic acid (1), caffeic acid (2), quercetin (3), naringin (4), icariside E4 (5), protocatechuic acid (6), (-)(2R,3R)-secoisolariciresinol (7), protocatechuic acid methyl ester (8), (±)-pinoresinol (9), piperitol (10), β-sitosterol (11), (+)-sesamin (12), 15α-hydroxy-ent-kaur-16-en-19-oic acid (13), and benzyl-O-β-D-glucopyranoside (14). Among these, compounds 5, 13, and 14 were isolated from the family Araliaceae for the first time, while compounds 2, 4~10, and 12~14 were isolated from A. trifoliatus for the first time. Notably, compounds 1~3 and 7, which exhibited α-glucosidase inhibitory activity, also possessed antioxidant activity.