Thirteen compounds isolated from the roots of Cynanchum auriculatum,which structures were determined as caudatin (1),qingyangshengenin (2),metaplexigenin (3),gagamine (4),kidjoranin (5),3-hydroxyacetophenone (6),4-hydroxyacetophenone (7),2,4-dihydroxyacetophenone (8),2,5-dihydroxyacetophenone (9),4-acetocatechol (10),baishouwubenzophenone (11),(+)-pinoresinol (12) and (-)-episyringaresinol (13) by comparison their NMR and ESI-MS data with the literature reported data.Among them,compounds 12 and 13 were isolated from this plant for the first time.All isolates were evaluated the scavenging activities on DPPH and ABTS.The results indicated that compound 10 had significant scavenging activities on DPPH and ABTS (IC₅₀ = 0.58 and 1.82 μg/mL,respectively).