Soft sediment deformation structures form due to disturbance of sediments during or after deposition, consolidation and burial. As one kind of widespread sedimentary structure, many studies focused on its classification and genesis. According to the genesis mechanism, Soft sediment deformation structurescan be classified as: (1) load structures, (2) convolute lamination and bedding, (3) deformed cross bedding, (4) slump sheets, (5) water escape structures and sediment injection structures, (6) collapse structures, (7) structures of biological and chemical origin. As an important and special structure, sesimite can be classified as syndepositional，penecontemporaneous and epigenetic deformationstructures．Many factors can act as the triggers for the soft sediment deformation structure, but the earthquake inducedliquefaction is the most important one. The trigger and mechanism of the soft sediment deformation are quite complex and can be identified by a process including faces analysis, trigger assessment and criterion assessment. Due to its important significance on many areas, the future study of the soft sediment deformation will be still focused on the classification and identification of the mechanism. The application on the civil geological engineering is also an aspect for many geologists. With the oil exploration from shallow water to deep water, it is another studying area to find the oil reservoir related with soft sediment deformation structures.