<p>The study of landslide dynamic process and impact intensity is of great significance to the qualitative and quantitative evaluation of landslides. This paper takes the Wangjiayan landslide as an example, establishes a more reasonable three-dimensional model based on high-precision DEM data, and uses PFC numerical simulation software to simulate the motion process and impact process of the landslide, respectively. By monitoring the characteristic parameters such as landslide velocity, displacement, energy, and impact strength, the dynamic features, energy conversion, and impact strength are linked to enriching the mechanism explanation of landslide dynamic features. The results show that the motion process of the Wangjiayan landslide lasted 34s, the main sliding time was 20s, the maximum displacement of the slide body was 358&#xa0;m, and the maximum velocity appeared at 10s, which was about 24&#xa0;m/s. During the landslide motion, the gravitational potential energy was mainly converted into collision and friction dissipation energy. According to the coordination of the slide body during movement, the Wangjiayan landslide can be roughly divided into four phases, namely, the chaotic phase of initial start-up, the coordinated phase of acceleration, the chaotic phase of high-speed steering, and the coordinated phase of deceleration, and the high-speed steering chaotic phase is the critical stage of energy dissipation. The impact strength at the foot of the slope is up to 2.4 × 10¹⁰ N. Both the impact strength and the final earth pressure decay exponentially with the increase of the distance from the rigid retaining wall to the foot of the slope.</p>