In high earth and rock dam engineering, the particle breakage and permeability characteristics of rockfill materials are important indicators that affect the physical and mechanical properties of dam materials. Indoor vibration tests were conducted on the scaled-down rockfill materials of Yulongkashi Hydropower Station to investigate the variations of parameters such as particle crushing and permeability coefficient of the rockfill materials under different vibration times.A three-dimensional structural model was established based on the particle size distribution curve, and seepage simulation was conducted on it. Changes in the pore structure and permeability characteristics of rockfill materials under different vibration and compacting durations were compared, and they were also compared with indoor experiments. Finally, some parameters affecting the permeability coefficient were subjected to fitting analysis, and the calculation formula for the permeability coefficient was obtained. The research results indicated that under the influence of vibration and compacting, the particle size distribution curve of the rockfill material became smoother, the particle arrangement became more compact, porosity, and permeability coefficient decreased, and water flow within the pore structure slowed down. The established three-dimensional structural model well reflected this process.