Abstract: The transpiration rate of tea plant was studied in slop lands of red soil regions．The results indicate that the daily variation of tea plant transpiration rate shows an obvious trend with a high value in midday and low values in the early morning and evening，however，there are some differences in the diurnal variation curves of tea plant transpiration rate in diferent days；the net radiation and air temperature are the two main factors affecting the transpiration rate of tea plant；there is a close correlation between the transpiration rate and stomata conductance，and with the stomata conductance increasing，the transpiration rate also increases Finally，the transpiration driving factors，the probability of preventing transpiration，the stomatal action’s regulation，and the water use efficiency of tea plant are discussed．