The study of temporal and spatial variation of ecological water requirement of forests under climate change plays an important role in effectively protecting water conserving forest and vegetation system, rational planning and managing basin water resources.With thedata of 11 meteorological stations in the upper reaches of the Hanjiang Basin from 1971 to 2010, this paper quantitatively studied the temporal and spatial variation of ecological water requirementof forests in this basin and its trend in the growing season from April to October based on the methodthat the ecological water requirement is calculated with evapotranspiration corrected by combinating the soil moisture and plant types. The paper also analyzed the sensitivity degree of the ecological water requirement to the changes of meteorological factors. Results showed that the annual average ecological water requirementof forests in the growing season in the upper reaches of Hanjiang River Basin was 6.9158 * 10~9m~3 and it had aninsignificant increasing trend overall and a distinct zonal characteristics in spatial distribution. The order of sensitivity degree of ecological water requirement to meteorological factors, from the highest to lowest, was maximum temperature, vapor pressure, solar radiation, winds and lowest temperature respectively. Furthermore, the distribution characteristics of the sensitivity is influenced by the regional latitude, altitude,vegetation type and underlying surface.