On the condition of constant temperature, grouping drywet soil with different initial water content and different time intervals, the experiments were carried out to study vaporous transfer, vaporousliquid transfer and the relationship of unsaturated expansive soil.And it was found that the soil behavior, water content and water content gradient were pivots for the transfer.Vaporous transfer, vaporousliquid transfer were increased with the increase of moisture gradient in a complex nonlinear relationship with times and locations.And with the less water, the adsorption capacity of soil was strong, resulting in larger gradient of moisture.While for larger water content, free water was more with more even of the moisture.