Abstract: Soil deformation and water seepage are ignored in the computation of slurry infiltration in traditional method. In this paper, the particle dispersion equation coupled with seepage velocity is derived according to the particle mass conversation, which highlights the dynamic properties of the suspended particles transport and deposition. The continuity equation for the suspension is proposed by modifying the water continuity equation in Biot's consolidation theory considering the e ect of particle deposition in slurry. Based on this, non-linear governing equations for slurry infiltration coupling deformation, infiltration and dispersion are derived and the corresponding variational principles are established. Finite element model based on the principles is established and the equations are solved with both incremental and iterative techniques. Computational results are validated by predicting the data from one-dimensional model test, and better agreement with the experimental data is shown compared to the traditional method which only considered particle convection and dispersion. The slurry infiltration in slurry trench is calculated with the method proposed in this paper. The deposition amount of slurry particles grows with the increasing depth, which indicates that a strict vertical degree control is needed during the shallow slurry trench construction. The excavating schedule can be determined considering the filled extent by the slurry particles according to the computation.