The authors adopt a new two-way land-atmosphere coupled model R42_AVIM. By contrast of experiments with and without vegetation cover, the possible impact of global vegetation distribution on climate and atmosphere circulation is discussed. The results show that the actual vegetation coverage on land can alter the surface characteristic parameters obviously on planetary scale, especially for tropical rainforest and boreal forest. Under the distribution of actual vegetation, the surface net radiation and the latent heat flux will increase, while the surface sensible heat flux will decrease. In the areas where the leaf area index (LAI) is relatively large, the surface temperature will decrease. Moreover, this effect can also extend to the middle and upper troposphere. In addition, the present vegetation distribution enhances the evaporation as well as the corresponding condensation latent heating in the tropics and mid-high latitudes, which makes the meridional circulation stronger. And then, the precipitation increases in the tropics and mid-high latitudes, while decreases in the subtropics. Meanwhile, vegetation can also reduce the sea-land temperature contrast and weaken the Asian summer monsoon.