[Objective] Reverse-graded deposits are prone to geological disasters under rainfall conditions. To comprehensively understand their seepage characteristics and disaster-causing mechanism, the indoor seepage test is conducted using typical deposits as the research object. The variation patterns of permeability across different deposit layers and the migration characteristics of fine particles were studied under different fine particle contents, dry densities, and infiltration heads. [Methods] Based on the Taheman deposit landslide, constant-head seepage experiments were performed using a seepage erosion device under different fine particle contents, dry densities, and infiltration heads. The influences of external hydraulic conditions and reverse-graded deposit characteristics on the permeability of each deposit layer were analyzed, and the migration patterns of fine particles within each layer were revealed. [Results] Fine particle content, dry density, and infiltration head exerted the greatest influence on the permeability variations in the upper rock-soil layers, followed by the middle rock-soil layers, with the least influence on the lower rock-soil layers. Higher fine particle content facilitated the accumulation and deposition of fine particles in the upper and middle rock-soil layers, resulting in a decrease in the soil permeability. Under varying infiltration heads, the permeability of the upper layers exhibited either an increase or decrease, while the middle and lower layers consistently showed permeability decline. Regardless of influencing factors, the permeability of the lower layers uniformly decreased. Fine particles(<0.075 mm) had obvious migration, loss, and deposition processes in the middle and upper rock-soil layers. The lower the soil layer was, the smaller the particle size of the fine particles it could retain. [Conclusion] The middle and upper parts of reverse-graded deposits exhibit weaker erosion resistance, where fine particles are prone to migration and loss, leading to reduced permeability. The erosion resistance of the middle section is stronger than that of the upper part, while the lower section demonstrates the highest erosion resistance. Fine particles are easily subject to deposition and accumulation, which reduces permeability. Factors such as fine particle content, dry density, and infiltration head have the greatest impact on permeability variations in the upper section, followed by the middle section, with the least effect on the lower section. When the seepage direction is top-down, significant particle migration occurs between the upper and middle layers, but fewer fine particles migrate and deposit into the lower layers. The ability to retain fine particles decreases with proximity to the lower part of the deposit. Due to the coarse-upper and fine-lower structure of reverse-graded deposits, particle migration and loss characteristics vary with different seepage directions, warranting further investigation in subsequent experiments.