Natural soil erosion and sediment are important parts of geologic cycle, but they have been accelerated by human activities and many eco-environmental problems arised. In a small watershed of purple hilly area, Sichuan province, the erosion-sediment sections were marked out basing on differences of topographic and soil features, and the characteristics of soils particle component as well as its fractal dimensions were also studied on the routine analyzing results. The results showed that: the erosion-sediment features of different spots on erosion-sediment trans/vertical section are different distinctively. Types of washing and denudation, moving, and sediment and burying, which components an erosion-sediment catena, can be distinguished. Sediment is main process on erosion-sediment vertical section. We can get more entire and whole understanding of erosion-sediment through dividing erosion-sediment section types. Particle components, especially clay contents, significantly embodied the differences of erosion-sediment. The trend of sand decreasing and clay increasing with altitude reduce is embodied synthetically through particle fractal dimension.