Abstract: With the development of engineering technology, it is of great significance and engineering application value to study the sliding mechanism of soil-rock slopes. The transparent soil model tests are used to study the contact mechanism of soil-rock interface and the internal movement law of slope soils under external force, and the visualization of internal deformation of soil-rock slopes is realized. The influences of Barton joint roughness coefficient, slope angle and soil thickness on slope stability are considered. Using the particle image velocity (PIV) and the laser speckle technique, the internal deformation characteristics of soil-rock slopes under external force are obtained. It is shown that the sliding of soil-rock slopes can be divided into three stages: initial stage, uniform stage and acceleration stage. In the sliding process, reducing the Barton joint roughness coefficient of rock mass, increasing the thickness of soil layer and increasing the slope angle will cause larger displacement in the soil body of the slopes, and then lead to the loss of soil-rock slopes. After adopting the slope protection measures of double-row anti-slide piles, the development of the internal displacement of slope soils is effectively delayed, and the stability of soil and rock slope is improved. The research results may provide an important theoretical basis for revealing the sliding mechanism of soil-rock slopes and the effectiveness of Engineering protection as well as an important experimental basis for visualizing the sliding of soil-rock slopes by tracking the trajectory of transparent soil particles.