For planning to set up "Taiwan Red Cypress Ecological Conservation Area of Duigaoyue", which is located in Xinyi Township, Nantou County, an investigation was conducted in Mar.- Dec., 2016. In total, 317 vascular plants, including 12 rare plants, and 99 giant trees (DBH > 100 cm) were recorded, including Chamaecyparis formosensis, Picea morrisonicola, Alnus formosana, Pasania kawakamii, and so on. The proposed Taiwan Red Cypress Ecological Conservation Area of Duigaoyue should be conserved in order to maintain biodiversity to provide ecological research and natural education.