In recent decades， a great increase of atmospheric CO₂ concentration has （［CO₂］） occurred due to fossil fuel combustion and industrialization， which has caused a series of ecological and environmental issues. One of the effects of the increase of ［CO₂］ is on evapotranspiration （ET）. ET is a component of surface energy balance and water balance， therefore， its change would influence the exchange between surface and atmosphere and water cycle directly. On the basis of a water-carbon coupled model named PML-V2 and the CMIP6 ［CO₂］ datasets， this study estimated two sets of vegetation transpiration （Ec） from 2001 to 2014. One simulation is static： the constant ［CO₂］ concentration in 2001 is fixed as input during the simulation from 2001 to 2014. The other was dynamic： time-varying ［CO₂］ was used during the simulation from 2001 to 2014. By comparing the two sets of Ec， the effects of ［CO₂］ on Ec were explored. The results showed that the reduction in Ec due to the increase of ［CO₂］ was smallest in summer and is largest in winter. From 2001 to 2014， this reduction is 0~5%. The largest effect occurred in the eastern and in the central areas of China. For ecosystems of forest， wetland， cropland and shrubland/savanna， the reduction of Ec due to the increase of ［CO₂］ is 15~20 mm/a till 2014. For grassland， the reduction is 5 mm/a. The sensitivity of the effects of the increase of ［CO₂］ on Ec to arid index， precipitation and air temperature indicated that Ec was the most sensitive to ［CO₂］ in the southeast of China.