Abstract: Intense rainfall infiltration in a short period was prone to causing soil and water loss on the slope surface, tensile cracks at the top of the slope, and the formation of dominant channels within the slope. Subsequently, this resulted in erosion and damage of the slope. To investigate the erosion mechanisms underlying loess slope failure under heavy rainfall conditions. It achieved this by dynamically monitoring the variations of moisture content within the slope, the infiltration rate, the advancement of the saturation surface, and the changes in displacement. This study utilized Yangling loess as the research subject and conducted large-scale model tests. These tests systematically examined the erosion processes and mechanisms of loess slopes under the influence of gravity, hydraulic forces, and the coupled effects of gravity and water. And proposed corresponding engineering recommendations. The results indicated that: (1) Under the effect of rainfall, the moisture content curve on the slope surface underwent variations such as "rapid increase during rainfall - tendency towards stability - decrease after rainfall - tendency towards stability" and "unchanged in the early stage of rainfall - rapid increase - tendency towards stability". Nevertheless, the moisture content within the slope merely increased partially. Consequently, the closer to the slope surface, the lower the soil strength and the more vigorous the movement. The infiltration rate v1 of the wetting front gradually diminished with the increase of infiltration depth, and v1 at the slope top was approximately three times that at the slope surface. Hence, its infiltration depth was greater than that of the slope surface. The wetting front in the slope top region presented an inverted S shape. The wetting front in the slope surface region was basically parallel to the slope surface. (2) The erosion of loess slopes was classified into three stages: local cracking (first at the slope top and then on the slope surface) - the development of erosion gullies and cracks at the slope top - slope surface sliding erosion and slope top collapse (first on the slope surface and then at the slope top). Among these processes, hydraulic erosion involved soil softening and local cracks, followed by the formation of erosion gullies and fracture development, and ultimately resulted in surface runoff erosion. Gravity erosion was a process characterized by solifluction - crest crack - crack coalescence and crest collapse. Mixed erosion was an advanced form of degradation that built upon both hydraulic and gravity erosion, resulting in more extensive and severe damage. (3) The control measures for the erosion and damage occurring on loess slopes should have commenced by reducing surface erosion and lowering the infiltration quantity at the slope top. It was proposed that the slope surface be covered with ecological bags, which could not only prevent erosion but also facilitate ecological restoration. It was suggested that impervious measures be established at the top of the slope to minimize the infiltration of rainwater from the top. It was recommended that the entire surface of the slope be sprayed with cement mortar to form a protective layer on the slope and the top of the slope, thereby avoiding infiltration. This study offers scientific prevention and control measures for the erosion and damage of loess slopes in the northwest area under the action of rainfall.