Abstract: In order to further clarify the main source of eroded sediment and dynamic changing process from the slope-gully systems in Loess Plateau, eroded sediment source from slope-gully systems was studied in Loess Plateau by using the indoor generalized slope-gully systems model and runoff scouring method, combining with rare-earth elements tracer technique. The results showed that the eroded sediment from slope was greater than that from gully in the experiment, and the eroded sediment yield from the top two meters on the slope accounted for the total sediment yield of 57%-74%. Under the scouring flow of 6, 8, 10 and 14 L/min, eroded sediment from various trace element erosion zones in the slope was in the order of La＞Ce＞Tb＞Sm, but in the flow of 12 L/min, which was in the order of La＞Ce＞Sm＞Tb. Slope erosion and sediment yield as a percentage lasted growth, showing a generally increasing trend of volatility, after 25 minutes it began to decrease. Gully erosion and sediment yield trends and changes were opposite to the slope. The study provides a scientific basis for the management of slope-gully systems in small watershed in Loess Plateau.