Abstract: Seepage erosion, such as piping and contact erosion, often occurs in dikes during flood seasons, which is also one of the hot research topics. However, the piping and contact erosion in dikes are not exactly the same as those defined in the soil mechanics. Starting from the related definition of seepage failure forms in the soil mechanics, combined with the seepage erosion failure model in recent years, combing the concept of piping and contact erosion in dikes, the piping in dikes is called backward erosion piping, and the contact erosion in dikes is classified into between different soils and between the building across dike and the dike body. The latter can be further classified into the concentrated leak erosion caused by poor contact between the building and the surrounding soil and by the cracked conduits.