As the moisture content of the expansive soil slope increases, a certain amount of lateral expansion deformation occurs, and a certain amount of lateral pressure is generated which is composed of the lateral expansion force generated by the constraint deformation of the surrounding soil and the lateral soil pressure caused by the self-weight of the soil and the overlying load. The lateral pressure, especia-lly the generation of lateral expansion force, is one of the main reasons for the shallow failure of the expansive soil slope. A lateral pressure test was conducted using a self-made instrument to control the late-ral strain, and the variation law of the lateral pressure under the influence of factors such as the lateral strain, overlying pressure, and wet-dry cycles was studied. The experimental results show that the late-ral pressure increases linearly with the overlying pressure, and the increase trend does not change with the influence of other conditions. The progress of wet-dry cycles will lead to a certain degree of reduction in the lateral pressure, but it will gradually stabilize after a certain number of cycles. The lateral pressure decreases significantly with the increase of lateral strain, but the decrease extent gradually decreases. Within the existing range of changes, the lateral strain has the most significant effect on lateral pressure, followed by the overlying pressure, and the impact of wet-dry cycles is relatively small.