Abstract: Abstract: As one of engineering measures for conserving soil and water, many check dams have been constructed on the Loess Plateau and played important roles in holding back eroded soil just like sediment ponds. Meanwhile, a lot of information on the erosion and sediment yield is recorded and preserved in the check dams. Understanding the sedimentary characteristics is an essential prerequisite for studying the sediment transport processes and laws for a watershed with check dams. A typical check dam without spillway located in the top of a branch gully in the Wangmaogou watershed in the Loess Hilly Area was selected for this study. In the check dam, 8 open test pits with a depth of 1.5-2.0 m were dug in the longitudinal section and cross section. The boundaries between sedimentation cycles were obvious, and the thickness of each sedimentary cycle and plough layer was measured. A total of 108 soil samples were collected from the 8 open test pits in the check dam. The plough layer was divided into upper (0-20 cm) and lower layers (below the depth of 20 cm). The soil samples were analyzed with the laser diffraction technique using a Mastersizer 2000 laser particle size analyzer, and the soil particle size fractions were determined. Based on the investigation on the sedimentary cycle thickness and particle size composition changes in different deposition profiles in the check dam in the study watershed, the redistribution characteristics of sediment deposition of each flood in the dam were studied. The results showed that the sediment deposition process in the dam had non-uniform distribution, and the differences of the sedimentary cycle thickness in both the longitudinal section and the cross section were obvious, and the fluctuation of early sedimentary cycle thickness was larger than that in the late years. When the rainstorm and sediment yield were large, the sediment thickness was larger and the difference was also large. On the contrary, the sediment thickness and the difference were relatively small. Thus, there was no relationship between the sediment thickness and the soil particle composition in the check dam. The average contents of clay, silt and sand were 4.66%, 58.78% and 36.56%, respectively, and the silt was the main sand size. The change of clay, silt and sand content in each vertical section in the dam was little, but in different locations in the check dam, the size classification occurred. From the tail to the head of the check dam, soil coarsening degree decreased significantly, and the soil particle size composition showed a gradual trend of fining. The mutations of particle size composition occurred in several sedimentary cycles, which had the indicative function on the occurrence of big rainstorm and flood. Combined with precipitation, sediment, topography in this watershed, it can help to reveal the dynamic processes of the flood. To better understand the sediment deposition process and distribution, more research is needed.