Aiming at the dynamic development process of piping in multi-stratum dike foundations, a finite element software was used to simulate the seepage field at different stages of piping. The hydraulic gradient in each area was compared to the critical hydraulic gradient for soil erosion in the corresponding area, so as to determine the erosion area at each stage of piping development. The results show that the occurrence of piping is marked by the breaking of the sandy interlayer in the case of the multi-stratum dike foundation with the burial depth of sandy interlayer of 1m. During the development of piping, the soil particles are eroded, and then the local soil permeability changes accordingly. The variation of permeability affects the distribution of seepage field, and then the loss of soil particles can be influenced. Therefore, the dynamic development of piping is a process in which soil erosion and permeability are influenced and coupled by each other. Multiple types of erosion occur in the development of piping, including the simultaneous effect of deep piping and shallow piping, resulting in a deep piping channel that can significantly in fluence dam safety.