Calycosin-7-O--D-glucopyranoside (CG), one major isoflavonoid in Radix Astragali with promising pharmacological effects, was separated with a low-cost process in the present study. The sequential separation and purification procedures established involved extraction with 90% (v/v) aqueous ethanol at 75C for 2h twice followed by partition with ethyl acetate, elution with water, and 40% (v/v) aqueous ethanol on a styrene-based resin column and recrystallization at 4C for 12h with methanol. These conditions resulted in recovery of 81.6% of total CG with over 97% purity.