Abstract: A horizontal slice method is presented to validly analyze the stability of slurry trench with the consideration of the soil anisotropy and the assumption of the soil boundary perpendicular to the trench face. The typical two-dimensional failure model is investigated, in which the wedge block is divided into slices. From the force equilibrium of each slice as well as its force and moment equilibrium, the models for 3Mand 4Mequations are established respectively. The model for 3Mequations is verified to be accurate, reliable and necessary. Finally, an example is provided to illustrate the variations of the factor of safety and the critical failure plane angle with the length of the groundwater table, surcharge loading, slurry height and slurry unit weight. The ratio of horizontal slice force to vertical slice force is defined to investigate the development of the horizontal slice force.