Abstract: The post construction settlement deformation of rock-fill dam is crucial to the safe operation of the dam. In order to analyze the stress characteristics of different skeleton structures of coarse-grained soils and the influence of filling factors on its compression deformation characteristics, sixteen groups confined compression test of coarse-grained soils are carried out through designing different coarse-grained content, density and moisture content. The experimental results show that the compactness of soil skeleton with the same initial void ratio and different coarse-grained content is different. With the increase of coarse-grained content, the change of void ratio of soil first increases and then decreases, and the soil with a grain content of 60% has the smallest porosity and the largest dry density after compression.After compression, the soil skeleton can be divided into coarse-grained suspension, coarse-grained bite, and coarsegrained overhead. Through range analysis, the density of soil has the greatest impact on its compression deformation,followed by the coarse content, and the moisture content has the least impact.