It is complicated to found continuity equation for unsaturated soil because of the uncertain volume of air phase. In order to solve this difficulty and to derive the consolidation equation for unsaturated soils with high degree of saturation, one-dimensional continuity equation of three-phase soil was created compactly in the principle of mass balance. Supposing Terzaghis principle of effective stress was still applicable to this type of soils, one-dimensional consolidation equation was derived. On basis of Terzaghis hypotheses and supposing that the degree of saturation was constant during consolidation, the analytical solution was presented. Then the consolidation characteristic of soils was analyzed. And It is shown: 1) the form of consolidation equation of soils with high degree of saturation is the same to Terzaghis one-dimensional equation, but the coefficient of consolidation is different. 2) Because of the instantaneous deformation, the degree of consolidation in early stage is much bigger than that of saturated soils, and subsequently the gap is reducing; when the time factor is 1.0, the degree of consolidation is almost equal to each other. 3) The time needed for soils with high degree of saturation to complete consolidation is extended comparing to the corresponding saturated soils; the smaller the degree of saturation is, or the more compressible the soils are, the bigger the ratio of time for completing consolidation is.