Abstract: The TDP (Thermal Dissipation Probe) technique was used to determine the sap flow density of Pinus massoniana, Schima superba and Liquidambar formosana in the growing season in the soil erosion area of Changting, Fujian Province, and the environmental factors were simultaneously recorded by using the automatic weather stations, in order to explore the physiological and ecological characteristics of water in the dominant plants and their responses to the environmental changes. The results showed that the diurnal dynamic changes of stem sap flow of Pinus massoniana, Schima superba and Liquidambar formosana had the same circadian rhythm, all showing the unimodal changes of high at noon and low in the morning and evening, and Schima superba had the highest sap flow density. The sap flow density of stems in the rainy days was obviously lower than that in the sunny days. The sap flow densities of the three plants were significantly correlated with the environmental factors such as the total solar radiation intensity, wind speed, air temperature, air relative temperature and soil temperature (P < 0.01), while not with rainfall (P>0.05). Among them, the air relative humidity had the strongest correlation with the sap flow density, followed by the air temperature and soil temperature.