To determine the effects of different doses of UV-B on the yield and quality of Scutellaria baicalensis under elevated CO₂, S. baicalensis seedlings of 60 days old were exposed to elevated CO₂ concentration for 60 days at different UV-B doses. The results indicated: (1) the activity of MDA, SOD and CAT increased with increasing doses of UV-B under ambient and elevated CO₂ conditions. At lower UV-B doses, elevated CO₂ treatment resulted in decreasing SOD and CAT activities while MDA suffered no changes. At higher UV-B doses and elevated CO₂  concentration, SOD and CAT activities increased while no MDA concentration was significant increased. (2) Lower UV-B radiation doses could improve S. baicalensis yield and quality. The best dose was 2.33 KJ·m^-1·day^-1. Although elevated CO₂ lead to higher yield of S. baicalensis, the quality was decreased. Therefore, a dose of UV-B of 2.33 KJ·m^-1·day^-1 was applied in agriculture planting to hinder the elevated CO₂ effect.