通过对水分胁迫下南方７个树种幼苗叶水势、相对水分亏缺、叶保水力、膜透性和根系活力等指标的测定和研究，比较各树种间的抗旱能力和机理。结果表明：水分胁迫下，各树种间维持水分平衡能力：银杏≈马尾松＞杉木≈火炬松＞苦楝≈水杉＞刺槐；膜伤害大小：马尾松＜银杏＜火炬松＜杉木＜苦楝＜刺槐＜水杉；根系活力大小：杉木≈马尾松≈银杏＞火炬松＞苦楝≈刺槐＞水杉。综合以上结果，７种苗木抗旱能力为：银杏≈马尾松＞杉木≈火炬松＞苦楝＞水杉≈刺槐。 Through the determination and research of the leaf water potential, relative water deficit, leaf water retention, membrane permeability and root activity of seven southern tree seedlings under water stress, the ability and mechanism of drought resistance among different tree species were compared. The results showed that: Under water stress, the water balance ability among the species was maintained: Gingko ≈ Masson pine> Cunninghamia lanceolata> Melia azedarach  Metasequoia glyptostroboides> Robinia pseudoacacia; the size of injury: Masson pine loblolly pine> neem ≈ acacia> metasequoia. Based on the above results, the drought tolerance of seven seedlings was as follows: ginkgo ≈ masson pine> fir ≈ loblolly pine> neem> metasequoia ≈ locust.