Abstract: Under the action of periodic fluctuation of reservoir water level,the rock and soil mass of the reservoir bank slope is in a dry-wet cycle state. The deterioration of the shear mechanical properties of the interface between the accumulation body and the bedrock is the key factor affecting the deformation and failure of the accumulation body bank slope. Therefore,a dry-wet cycle test of the soil-rock interface was designed. The shear stress-shear displacement curve of the soil-rock interface can be divided into the elastic stage,yield stage,and plastic stage. It has no obvious peak,showing a slight plastic hardening phenomenon. The shear strength of the soil-rock interface decreases gradually under the action of dry-wet cycles,and the overall trend of non-uniform deterioration is steep at first and then slows. After 12 dry-wet cycles,the cohesion and internal friction angle reduced by 37.45% and 22.12%,respectively. In comparison,the cohesion deteriorates more than the internal friction angle. Moreover,the degradation of shear strength of the soil-rock interface caused by the first five dry-wet cycles accounts for about 80% of the total degradation. The main reasons for the deterioration of shear performance of the soil-rock interface are the deterioration of soil and rock strength,bedrock surface roughness,and the adhesion degree of the soil-rock interface under dry-wet cycle action.