This study is to diagnose the drought tolerance of twenty broad-leaved tree species by the pressure-volume (P-V) curves. As for the diagnosis of drought tolerance, the valuable water relations parameters obtained from P-V curves are the osmotic potential at full turgor, Ψ_0^(sat), osmotic potential at incipient plasmolysis, Ψ_0^(up), maximum bulk modulus of elasticity, E_(max), and relative water content at incipient plasmolysis, RWC^(up) Also, the figures related to the diagnosis of drought tolerance are the free water content (FWC) versus leaf water potential(Ψ_L), volume-averaged turgor pressure (P_(vat)) versus leaf water potential (Ψ_L), and Ho¨fler diagram. In this study, the relatively high drought tolerant species are Fraxinus rhynchopleylla, Quercus hcutissima, Quercus serrata, Quercus aliena, and Pcrpulus alba×glandulosa : the relatively low drought tolerant species are Fraxinus mandshurzca, Betula platyp6aylla var. japonica, Populus euramericana, Kalapanax pictum, Carpinus loxiflora, Carpinus cordata, Prunus cargentii, Prunus leveilleana, and Corraus controversy ; medium species are Quercus mongolica, Acer mono, Acer triflorum, Acer pseredo-sieboldianum, Ulmus davidiana, and Zelkova serrata.