To realize difference of water potential of different tree specie and to find a theoretical basis for evaluating drought-enduring capacity of plants in karst area，6 tree species seedlings change of leaf water potential and relationship between leaf potential and environment factors have been studied at different growing stages. The result show that: (1)Daily variation characteristic of leaf potential of 6 tree species seedlings was single (Platycladus orientalis (Linn.)Franco、Cinnamomum camphora (Linn.)Presl、Elaeocarpus sylvestris(Lour.)Poir) or double (Fokienia hodginsii (Dunn) Henry et Thomas、Robinia pseudoacacia L．、Broussonetia papyrifera) peak curves; (2)Leaf water potential of 6 tree species seedlings was maximal in early growth stage (April). With increase of temperature it decreased and it was minimal in peak of growth stage (August). Subsequently leaf water potential increased with decrease of temperature. Increase extent of leaf water potential was different in different tree species. (3)Absolute value of 6 tree species seedlings leaf water potential and temperature all show positive correlation relationship in different growth stage, while it shows negative correlation relationship with atmospheric moisture.