Abstract:Slope topography changes are the important factors that affect the characteristics of eroded sediment particles. A deep understanding of the relationship between topographic factors and eroded sediment particle size composition and sorting characteristics is the basis for studying slope soil erosion dynamics. In this study, field rainfall experiments and particle size analysis experiments were used, combined with ArcGIS system identification and extraction to obtain topographic factor data, to study the characteristics of erosion and sediment particles in the low mountain and hilly areas and their relationship with topographic factors. The results showed that: (1) Under the test conditions, the total contents of clay and silt particles in the eroded sediment were much higher than that of sand particles. The content of coarse particles had a significant positive correlation with the slope factor (p<0.01), and a significantly negative correlation (p<0.05) with the accumulation of depressions. (2) In this study, the average mass diameter (MWD) of the test plot varied from 0.031 to 0.164 mm, and the fractal dimension (D) varied from 2.021 to 2.778. The determining factor of the MWD and D size was the content of coarse particles. From an overall point of view, rain intensity had a significant impact on the sediment particle sorting characteristic parameters. MWD increased with the increase of rain intensities, and D decreased with the increase of rain intensities. The two have a significant correlation with the slope factor (p<0.05). (3) The regression results show that the MWD and D had the significant power function relationships with the slope factor and the accumulation of depressions (R2>0.5). Combining the results of the correlation study, the slope factor was suggested as the preferred choice for the study of erosion and sediment particle size models. This study aimed to reveal the effect mechanism of topographical factors on slope erosion and sediment particles, and provide a scientific reference for the construction of soil erosion models.