The conservation of earthen sites is a newly emerging science. Although there have been great advances in the research of the earthen-site conservation and the earthen-site science has already a prototype, its theoretical systems are still not mature and no norm has been formed. Moreover, the protection technique of earthen sites can’t still satisfy the need for protection engineering. However, along with advanced technical application and increasing society’s demanding, the earthen-site conservation science will enter a fast developing period.