The study of new physics and technologies at the limit of nuclear stability is one of the frontiers of nuclear science based on big facilities. Unstable nuclei cover broad area in nuclear chart. Since mid-eighties of the last century, many new phenomena and new effects have been discovered in this area, such as shell evolution, new structure degrees of freedom and new effective interactions. The research at this domain is also closely related to the explosive astrophysical processes and the equation of state of the nuclear matter. In addition the synthesis of nuclei around the super-heavy island might also be relying on the knowledge of neutron-rich unstable nuclei. Due to the exciting science objects, a number of new unstable nuclear beam facilities will be constructed world wide.