Abstract: The atmospheric general circulation model coupled to the mixed layer ocean model has been used to simulate the changes of the global soil moisture.Comparing the simulated results with observations is shown that the model is capable of doing sensitive ezperiments about the carbon dioxide changes.The 2×CO2/1×CO2 comparison shows that there are the obvious changes of the soil moisture in the global for four seasons.There are the wet soil moisture in the lower latitudes of both hemispheres and dry soil moisture in the middle latitudes of both hemispheres for four seasons.The dry soil moisture in summer and wet in other seasons are found in the northern higher latitudes.The analyses of the physical mechanisms responsible for the CO2-induced changes of soil moisture show that the budgets of the surface water and heat are the important factors.