The physical and mechanical properties of road slope soil in the middle reaches of Bailong River are prone to deteriorate under the action of intense wet and dry environment formed by summer centralized rainfall and high surface temperature, resulting in deformation and instability of road slope soil. In order to study the deterioration process of highway slope soil under such dry and wet effects, the soil mass of Huama landslide was selected as the research object, and the indexes of particle gradation, density, liquid-plastic limit, shear strength and uniaxial compressive strength of soil mass after several intense dry and wet effects and daily dry and wet effects were tested. The results showed that the above indexes changed significantly after several different dry and wet cycles, and the change rate of each index of the sample after intense dry and wet cycles was greater than that of daily dry and wet cycles. The compressive strength decreased by 7.9% and 6.2%, the cohesion decreased by 9.2% and 7.9%, and the internal friction angle increased by 25.4% and 20.6%, respectively. The results show that the sand content in the soil decreases, the clay content increases, the porosity increases, and the particle uniformity increases, the porosity increases, and the roundness deteriorates, which are the main reasons for the soil deterioration in this area. It provides useful reference for highway construction and geological disaster prevention and control in this area.des useful reference for road construction and geological disaster prevention and control in this area.