The total phenolic compounds content, flavonoid content, antioxidant, and acetylcholinesterase inhibitory activities of Houttuynia cordata (HC), Perilla frutescens (PF), green tea (GT), and their mixture extracts were evaluated using in vitro assays. First, a mixed design method was performed to derive the optimal mixing ratio, and a total of 11 mixing ratios were set. The DPPH radical scavenging activity and peroxynitrite scavenging activity were significantly higher in HC, PF, GT and their mixture extracts. The DPPH radical scavenging activities of GT, HC：PF：GT = 2：1： 2, 1：1：3 and 1：2：2 extracts was more than 94% at a 25.6 μg/mL concentration. The HC：PF：GT = 1：2：2 and 1：1：3 extracts showed higher peroxynitrite scavenging activity than the positive control, L -penicillamine, indicating very high antioxidant activity. The HC：PF：GT = 1：1：3 extract showed the most active acetylcholinesterase inhibition assay compared to the other extract mixtures. The total phenolic compounds content was high in the HC：P F：GT = 1：1：3 extract and the total flavonoid content was high in the HC extract. These results suggest that the mixed extracts of HC, PF and GT have antioxidant and acetylcholinesterase inhibitory effects.