The purpose of this study Is to recommand all kinds of library in Korea to develop a disaster plan. The materials in the library are apt to get damaged at once by such disasters as fire or flood etc. It is fortunate that we Have not found any big disaster at libraries in Korean. considering many cases of big disaster which distroy materials at library in foreign countries. In spite of the posibility of disaster any time, that will make librry loss of function, there are no library that have a disaster plan in Korea. Disaster plan is a guidance by which materials are conserved at ordinary times, protected and recoverd in contingency. It consists by four elements: prevention, preparedness, reaction and recovery. As libraries function by biblogrophic data and user data in automation system, it is also recommended to prepare system protection in the disaster plan.