Abstract: The stable carbon isotope composition (δ¹³C) of the leaves of Pinus massoniana and Schima superba in the soil and water loss area of Changting, Fujian Province was determined by using the stable carbon isotope method to indicate the long-term water use efficiency (WUE) of the two plants, in order to explore the water use efficiency characteristics, strategies and competitiveness of the dominant tree species in the process of ecological restoration. The results showed that:the carbon isotope composition (δ¹³C) and water use efficiency (WUE) of the leaves of Pinus massoniana increased significantly with the improvement of ecological restoration degree, and were relatively stable during its growth and development. The δ¹³C value and WUE of the leaves of Schima superba decreased significantly with the improvement of ecological restoration degree, and had greater plasticity on the ime scale. The difference of water use strategy between Pinus massoniana and Schima superba might be resulted from the difference of biological characteristics between coniferous tree species and broadleaved tree species.