In this study, we examined the antioxidant activity of the Sumaeyaksuk (Artemisia argyi) tea extracts from different pre-treatment and extraction methods. Sumaeyaksuk was sun-dried for 3.5 days (control, RC) and aged at a temperature of 60℃ for 3.5 days (HA), 7 days (HB), and 14 days (HC), respectively. Each sample was extracted in 60℃ and 95℃ hot water for 2 minutes. The soluble solids content of HA from the 60℃ and 95℃ hot water extraction were 0.52±0.18% and 0.92±0.18%, respectively. The soluble solids content was increased by the higher extraction temperature. The reducing sugar content of RC was 9.55±0.18 mg/g in the 95℃ extraction, which was significantly higher than in the 60℃ extracted sample. However, the reducing sugar content did not show a remarkable difference based on aging periods. The total phenolic compound content of the 95℃ extracted samples was 3.36±0.13~9.88±0.23 mg/g, which was significantly higher than that of the 60℃ extracted sample. The ABTS radical scavenging activity of the 60℃ extracted RA and HA samples were 35.63% and 95.10%, respectively. Moreover, the radical scavenging activity increased to 63.35% and 96.78%, respectively, in the 95℃ extracted samples. As a result of the high temperature, the extracted sample showed an increase in the FRAP. In the RC sample, the FRAP was two times higher in the 95℃ extracted sample (181.28±2.90 μM) than in the 60℃ extracted sample (83.88±0.43 μM).