To obtain the information on antioxidant activity by harvesting parts and time in Cudrania tricuspidata Bureau, total phenolic contents, flavonoid contents, superoxide dismutase (SOD) like activity and 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging activity of methanol extracts from Cudrania tricuspidata were investigated. Total phenolic contents was the highest in leaf [30.2~38.8 mg/g dry weight (DW)] and followed by root bark, stem bark, fruit, root except bark and stem except bark. Among harvesting time, total phenolic contents of leaf was the highest as 38.1~38.8 mg/g DW in May and June, and then decreased to October. Root bark harvested in April and May contained 26.6~27.8 mg/g DW total phenolic compounds and total phenolic content fell to a very low values at 1.8 mg/g DW in February. Flavonoid contents was very high in leaf and root bark. Especially, root bark harvested in April had the highest of flavonoid contents as 23.2 mg/g DW. As a result of simple linear regression analysis of total phenolic contents on flavonoid contents according to harvesting parts, it showed a high correlation (p 〈 0.001) with 0.57~0.97 R2 (coefficient of determination). As RC50 value, that was, the concentration of sample required for 50% reduction of DPPH absorbance, was 13.7~20.5 μg/mL in leaf so DPPH radical scavenging activity was very high. But SOD like activity of 1,000 μg extract/mL MeOH was a low value of 0.3~9.2% in all samples.