Abstract: The correlation between environmental factors and transpiration intensity, the total transpiration and evapotranspiration of the secondary oak stands were studied in this paper. The results show: The major environmental factors affecting transpiration intensity are the net radiationthe air temperature respetively. The relative humidity and the soil heat fluxes are the second. The wind velocity and the average water capacity of soil are unremarkable. In the all growing season, the transpiration of Quercus variabilis is 380.46mm, and that of Liquidambar Formosana is 48.42mm. The total transpiration of the secondary oak stand amounted for 428.88mm. The total evapotranspiration of the secondary oak stand is 825.68mm,which make up 68.85 percent of the precipitation in 1996.