From the definition of system, background and process of Earth System Science are reviewed simply. The earth system science has become a focus and hotspot in Geo sciences field, and is driving and accelerating the development of geo information science, land system science and globe change study. The special location of coastal zone in earth system is discussed in detail. Coastal zone study plays an important role in earth system science. The front of coastal zone study, LOCIZ, is also introduced briefly in this paper.