Abstract: Based on the incremental nonlinear consolidation theory for unsaturated soil and the relative dry density as the internal variable, the bidirectional coupling analysis of soil deformation and water transfer of a high fill project in Yan′an New District of northern Shaanxi is carried out.The influences of the post-construction settlement of the fill and rainfall infiltration on its settlement and water distribution are predicted.The results show that compared with the traditional double-line method, the incremental nonlinear consolidation theory for unsaturated soil can simulate the process of construction and rainfall and the deformation of soil and the movement of water in soil at the same time.Especially it can make the calculated results be more reasonable by considering the bidirectional coupling effect between the soil deformation and water transfer.