The physicochemical properties and antioxidant activities of hot water extracts of Quercus salicina Blume (QS), Ligustrum japonicum (LJ), and Clerodendron trichotomum (CT) leaves were investigated. Hot water extracts of QS, LJ, and CT leaves were prepared at different temperatures (70, 80, and 90 ) and times (1, 2, 3, 4, and 5 h). The lightness (L*), redness (a*) value, pH and soluble solid contents of QS extract were lower than those of other extracts. Compared with the LJ and CT extracts, QS extract showed increased total phenolic (533.11 to 692.67 μg GAE/g) and flavonoid (42.13 to 58.40 μg CE/g) contents and higher 1.1-diphenyl-2-picrylhydrazyl (DPPH, 30.21 to 43.02%), and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS, 26.08 to 28.28%) radical scavenging activities. CT extract showed low total phenolic (212.22 to 361.11 μg GAE/g) and flavonoid (8.93 to 22.60 μg CE/g) contents, as well as DPPH (5.37 to 11.23%), and ABTS (12.17 to 21.47%) radical scavenging activities at all extraction conditions. For QS, LJ, and CT extracts, the extraction conditions that provided optimal physicochemical properties and antioxidant activities were 80 for 3 h, 90 for 4 h, and 90 5 h, respectively.