In order to study the problems of slurry shield filter cake formation in sandy pebble stratum, the self-made equipment was used to carry out permeability tests to observe the process of filter cake formation in the sandy pebble stratum. The morphology of the accumulation of slurry particles in the stratum has been analyzed in detail to explore the mechanism of slurry infiltration and filter cake formation. Based on the FLUENT-EDEM coupling method, a slurry infiltration numerical model is established. The results show that the three permeability states of the filter cake depend on the particle ratio of the slurry and stratum. Under the same conditions, the slurry penetration depth decreases with the increase of slurry density, and increases with the increase of slurry pressure. The influence of pressure is small. The numerical simulation results can reflect the phenomenon of indoor experiments, and the conclusions can provide reference for the selection of shield construction parameters.